
Doug's Headers D303Y-B 1 3/4" Tri-Y Header Chevrolet Truck Big Block Chevrolet 68-87 Hi-Temp Black Coating
Doug's Headers D303Y-B 1 3/4" Tri-Y Header Chevrolet Truck Big Block Chevrolet 68-87 Hi-Temp Black Coating
Product Info
Product Info
- 3/8" Thick machined flanges...no warping
- CNC mandrel bent tubes... accurate fit & better flow
- Tri-Y headers yield maximum power from off idle to 4500 RPM making them well suited for applications demanding maximum mid-range torque with maximum fuel economy
- Heavy 16 gauge tubing...longer life
- Tubes are pre-polished to remove scratches and the header is finished with a Hi-Temp Black Coating
Applications and Footnotes
Chevrolet - Class A (chevrolet chassis) |
||||||||||||
EMISSION | AUTO | STD | TUBE | COLLECTOR | PORT | |||||||
YEARS | ENGINES | CODE | A/C | P/B | P/S | COL | FLR | COL | FLR | SIZE (in.) | SIZE (in.) | SHAPE |
75 - 91 | 396-502 |
|
Y | Y | Y | Y | Y | N | N | 1 3/4 - 2 | 2 1/2 | SAP |
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Carbureted applications only | ||||||||||||
Fits P30 chassis | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design | ||||||||||||
Chevrolet/GMC - GMC 2WD TRUCKS & SUV |
||||||||||||
EMISSION | AUTO | STD | TUBE | COLLECTOR | PORT | |||||||
YEARS | ENGINES | CODE | A/C | P/B | P/S | COL | FLR | COL | FLR | SIZE (in.) | SIZE (in.) | SHAPE |
68 - 87 | 396-502 |
|
Y | Y | Y | Y | Y | Y | Y | 1 3/4 - 2 | 2 1/2 | SAP |
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Big block frame stands and motor mounts must be used to insure proper engine location and header fit. | ||||||||||||
Does not fit 4 speed applications with bell housing mounts | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design | ||||||||||||
Chevrolet/GMC - 1/2, 3/4, 1 Ton / 1500, 2500, 3500 TRUCKS |
||||||||||||
EMISSION | AUTO | STD | TUBE | COLLECTOR | PORT | |||||||
YEARS | ENGINES | CODE | A/C | P/B | P/S | COL | FLR | COL | FLR | SIZE (in.) | SIZE (in.) | SHAPE |
68 - 87 | 396-502 |
|
Y | Y | Y | Y | Y | Y | Y | 1 3/4 - 2 | 2 1/2 | SAP |
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Big block frame stands and motor mounts must be used to insure proper engine location and header fit. | ||||||||||||
Does not fit 4 speed applications with bell housing mounts | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design | ||||||||||||
Chevrolet/GMC - 4 Ton / 3500 Crew, Standard Cab DUALLY |
||||||||||||
EMISSION | AUTO | STD | TUBE | COLLECTOR | PORT | |||||||
YEARS | ENGINES | CODE | A/C | P/B | P/S | COL | FLR | COL | FLR | SIZE (in.) | SIZE (in.) | SHAPE |
73 - 91 | 396-502 |
|
Y | Y | Y | Y | Y | Y | Y | 1 3/4 - 2 | 2 1/2 | SAP |
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Big block frame stands and motor mounts must be used to insure proper engine location and header fit. | ||||||||||||
Does not fit 4 speed applications with bell housing mounts | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design | ||||||||||||
Chevrolet/GMC - 8 Ton / 3500 Crew, Standard Cab DUALLY |
||||||||||||
EMISSION | AUTO | STD | TUBE | COLLECTOR | PORT | |||||||
YEARS | ENGINES | CODE | A/C | P/B | P/S | COL | FLR | COL | FLR | SIZE (in.) | SIZE (in.) | SHAPE |
73 - 91 | 396-502 |
|
Y | Y | Y | Y | Y | Y | Y | 1 3/4 - 2 | 2 1/2 | SAP |
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Big block frame stands and motor mounts must be used to insure proper engine location and header fit. | ||||||||||||
Does not fit 4 speed applications with bell housing mounts | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design | ||||||||||||
Chevrolet/GMC - Blazer / Jimmy, Suburban, Tahoe / Yukon |
||||||||||||
EMISSION | AUTO | STD | TUBE | COLLECTOR | PORT | |||||||
YEARS | ENGINES | CODE | A/C | P/B | P/S | COL | FLR | COL | FLR | SIZE (in.) | SIZE (in.) | SHAPE |
68 - 87 | 396-502 |
|
Y | Y | Y | Y | Y | Y | Y | 1 3/4 - 2 | 2 1/2 | SAP |
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Does not fit 4 speed applications with bell housing mounts | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design |
Applications and Footnotes
Chevrolet - Class A (chevrolet chassis) |
||||||||||||
YEARS | 75 - 91 | |||||||||||
ENGINES | 396-502 | |||||||||||
EMISSION CODE |
|
|||||||||||
A/C | Y | |||||||||||
P/B | Y | |||||||||||
P/S | Y | |||||||||||
AUTO COL | Y | |||||||||||
AUTO FLR | Y | |||||||||||
STD COL | N | |||||||||||
STD FLR | N | |||||||||||
TUBE SIZE (in.) | 1 3/4 - 2 | |||||||||||
COLLECTOR SIZE (in.) | 2 1/2 | |||||||||||
PORT SHAPE | SAP | |||||||||||
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Carbureted applications only | ||||||||||||
Fits P30 chassis | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design | ||||||||||||
Chevrolet/GMC - GMC 2WD TRUCKS & SUV |
||||||||||||
YEARS | 68 - 87 | |||||||||||
ENGINES | 396-502 | |||||||||||
EMISSION CODE |
|
|||||||||||
A/C | Y | |||||||||||
P/B | Y | |||||||||||
P/S | Y | |||||||||||
AUTO COL | Y | |||||||||||
AUTO FLR | Y | |||||||||||
STD COL | Y | |||||||||||
STD FLR | Y | |||||||||||
TUBE SIZE (in.) | 1 3/4 - 2 | |||||||||||
COLLECTOR SIZE (in.) | 2 1/2 | |||||||||||
PORT SHAPE | SAP | |||||||||||
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Big block frame stands and motor mounts must be used to insure proper engine location and header fit. | ||||||||||||
Does not fit 4 speed applications with bell housing mounts | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design | ||||||||||||
Chevrolet/GMC - 1/2, 3/4, 1 Ton / 1500, 2500, 3500 TRUCKS |
||||||||||||
YEARS | 68 - 87 | |||||||||||
ENGINES | 396-502 | |||||||||||
EMISSION CODE |
|
|||||||||||
A/C | Y | |||||||||||
P/B | Y | |||||||||||
P/S | Y | |||||||||||
AUTO COL | Y | |||||||||||
AUTO FLR | Y | |||||||||||
STD COL | Y | |||||||||||
STD FLR | Y | |||||||||||
TUBE SIZE (in.) | 1 3/4 - 2 | |||||||||||
COLLECTOR SIZE (in.) | 2 1/2 | |||||||||||
PORT SHAPE | SAP | |||||||||||
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Big block frame stands and motor mounts must be used to insure proper engine location and header fit. | ||||||||||||
Does not fit 4 speed applications with bell housing mounts | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design | ||||||||||||
Chevrolet/GMC - 4 Ton / 3500 Crew, Standard Cab DUALLY |
||||||||||||
YEARS | 73 - 91 | |||||||||||
ENGINES | 396-502 | |||||||||||
EMISSION CODE |
|
|||||||||||
A/C | Y | |||||||||||
P/B | Y | |||||||||||
P/S | Y | |||||||||||
AUTO COL | Y | |||||||||||
AUTO FLR | Y | |||||||||||
STD COL | Y | |||||||||||
STD FLR | Y | |||||||||||
TUBE SIZE (in.) | 1 3/4 - 2 | |||||||||||
COLLECTOR SIZE (in.) | 2 1/2 | |||||||||||
PORT SHAPE | SAP | |||||||||||
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Big block frame stands and motor mounts must be used to insure proper engine location and header fit. | ||||||||||||
Does not fit 4 speed applications with bell housing mounts | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design | ||||||||||||
Chevrolet/GMC - 8 Ton / 3500 Crew, Standard Cab DUALLY |
||||||||||||
YEARS | 73 - 91 | |||||||||||
ENGINES | 396-502 | |||||||||||
EMISSION CODE |
|
|||||||||||
A/C | Y | |||||||||||
P/B | Y | |||||||||||
P/S | Y | |||||||||||
AUTO COL | Y | |||||||||||
AUTO FLR | Y | |||||||||||
STD COL | Y | |||||||||||
STD FLR | Y | |||||||||||
TUBE SIZE (in.) | 1 3/4 - 2 | |||||||||||
COLLECTOR SIZE (in.) | 2 1/2 | |||||||||||
PORT SHAPE | SAP | |||||||||||
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Big block frame stands and motor mounts must be used to insure proper engine location and header fit. | ||||||||||||
Does not fit 4 speed applications with bell housing mounts | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design | ||||||||||||
Chevrolet/GMC - Blazer / Jimmy, Suburban, Tahoe / Yukon |
||||||||||||
YEARS | 68 - 87 | |||||||||||
ENGINES | 396-502 | |||||||||||
EMISSION CODE |
|
|||||||||||
A/C | Y | |||||||||||
P/B | Y | |||||||||||
P/S | Y | |||||||||||
AUTO COL | Y | |||||||||||
AUTO FLR | Y | |||||||||||
STD COL | Y | |||||||||||
STD FLR | Y | |||||||||||
TUBE SIZE (in.) | 1 3/4 - 2 | |||||||||||
COLLECTOR SIZE (in.) | 2 1/2 | |||||||||||
PORT SHAPE | SAP | |||||||||||
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Does not fit 4 speed applications with bell housing mounts | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design |
Highlights
Highlights
- 3/8" Thick machined flanges...no warping
- CNC mandrel bent tubes... accurate fit & better flow
- Tri-Y headers yield maximum power from off idle to 4500 RPM making them well suited for applications demanding maximum mid-range torque with maximum fuel economy
- Heavy 16 gauge tubing...longer life
- Tubes are pre-polished to remove scratches and the header is finished with a Hi-Temp Black Coating
Applications and Footnotes
Applications and Footnotes
Chevrolet - Class A (chevrolet chassis) |
||||||||||||
YEARS | 75 - 91 | |||||||||||
ENGINES | 396-502 | |||||||||||
EMISSION CODE | ||||||||||||
A/C | Y | |||||||||||
P/B | Y | |||||||||||
P/S | Y | |||||||||||
AUTO COL | Y | |||||||||||
AUTO FLR | Y | |||||||||||
STD COL | N | |||||||||||
STD FLR | N | |||||||||||
TUBE SIZE (in.) | 1 3/4 - 2 | |||||||||||
COLLECTOR SIZE (in.) | 2 1/2 | |||||||||||
PORT SHAPE | SAP | |||||||||||
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Carbureted applications only | ||||||||||||
Fits P30 chassis | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design | ||||||||||||
Chevrolet/GMC - GMC 2WD TRUCKS & SUV |
||||||||||||
YEARS | 68 - 87 | |||||||||||
ENGINES | 396-502 | |||||||||||
EMISSION CODE | ||||||||||||
A/C | Y | |||||||||||
P/B | Y | |||||||||||
P/S | Y | |||||||||||
AUTO COL | Y | |||||||||||
AUTO FLR | Y | |||||||||||
STD COL | Y | |||||||||||
STD FLR | Y | |||||||||||
TUBE SIZE (in.) | 1 3/4 - 2 | |||||||||||
COLLECTOR SIZE (in.) | 2 1/2 | |||||||||||
PORT SHAPE | SAP | |||||||||||
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Big block frame stands and motor mounts must be used to insure proper engine location and header fit. | ||||||||||||
Does not fit 4 speed applications with bell housing mounts | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design | ||||||||||||
Chevrolet/GMC - 1/2, 3/4, 1 Ton / 1500, 2500, 3500 TRUCKS |
||||||||||||
YEARS | 68 - 87 | |||||||||||
ENGINES | 396-502 | |||||||||||
EMISSION CODE | ||||||||||||
A/C | Y | |||||||||||
P/B | Y | |||||||||||
P/S | Y | |||||||||||
AUTO COL | Y | |||||||||||
AUTO FLR | Y | |||||||||||
STD COL | Y | |||||||||||
STD FLR | Y | |||||||||||
TUBE SIZE (in.) | 1 3/4 - 2 | |||||||||||
COLLECTOR SIZE (in.) | 2 1/2 | |||||||||||
PORT SHAPE | SAP | |||||||||||
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Big block frame stands and motor mounts must be used to insure proper engine location and header fit. | ||||||||||||
Does not fit 4 speed applications with bell housing mounts | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design | ||||||||||||
Chevrolet/GMC - 4 Ton / 3500 Crew, Standard Cab DUALLY |
||||||||||||
YEARS | 73 - 91 | |||||||||||
ENGINES | 396-502 | |||||||||||
EMISSION CODE | ||||||||||||
A/C | Y | |||||||||||
P/B | Y | |||||||||||
P/S | Y | |||||||||||
AUTO COL | Y | |||||||||||
AUTO FLR | Y | |||||||||||
STD COL | Y | |||||||||||
STD FLR | Y | |||||||||||
TUBE SIZE (in.) | 1 3/4 - 2 | |||||||||||
COLLECTOR SIZE (in.) | 2 1/2 | |||||||||||
PORT SHAPE | SAP | |||||||||||
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Big block frame stands and motor mounts must be used to insure proper engine location and header fit. | ||||||||||||
Does not fit 4 speed applications with bell housing mounts | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design | ||||||||||||
Chevrolet/GMC - 8 Ton / 3500 Crew, Standard Cab DUALLY |
||||||||||||
YEARS | 73 - 91 | |||||||||||
ENGINES | 396-502 | |||||||||||
EMISSION CODE | ||||||||||||
A/C | Y | |||||||||||
P/B | Y | |||||||||||
P/S | Y | |||||||||||
AUTO COL | Y | |||||||||||
AUTO FLR | Y | |||||||||||
STD COL | Y | |||||||||||
STD FLR | Y | |||||||||||
TUBE SIZE (in.) | 1 3/4 - 2 | |||||||||||
COLLECTOR SIZE (in.) | 2 1/2 | |||||||||||
PORT SHAPE | SAP | |||||||||||
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Big block frame stands and motor mounts must be used to insure proper engine location and header fit. | ||||||||||||
Does not fit 4 speed applications with bell housing mounts | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design | ||||||||||||
Chevrolet/GMC - Blazer / Jimmy, Suburban, Tahoe / Yukon |
||||||||||||
YEARS | 68 - 87 | |||||||||||
ENGINES | 396-502 | |||||||||||
EMISSION CODE | ||||||||||||
A/C | Y | |||||||||||
P/B | Y | |||||||||||
P/S | Y | |||||||||||
AUTO COL | Y | |||||||||||
AUTO FLR | Y | |||||||||||
STD COL | Y | |||||||||||
STD FLR | Y | |||||||||||
TUBE SIZE (in.) | 1 3/4 - 2 | |||||||||||
COLLECTOR SIZE (in.) | 2 1/2 | |||||||||||
PORT SHAPE | SAP | |||||||||||
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Does not fit 4 speed applications with bell housing mounts | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design |
Additional Information
Additional Information
Doug's 2/4 WD TRUCK HEADERS Tri-Y Hi-Temp Black Coated Header development and design is complex and requires a substantial amount of time and resources to do the job right! Many manufacturers are unwilling to make the commitment and instead offer compromised headers at lower prices. Doug's will not compromise performance, quality or fit to compete with inferior designs at cheap prices. Every Doug's header is tuned with the proper tube size and length to efficiently remove all the exhaust from each cylinder, reducing pumping losses resulting in a dramatic increases in horsepower and torque. Doug's headers are carefully developed on the vehicles they are intended to fit and are re-checked numerous times during the design and manufacturing process.
Download instruction manual
Download instruction manual
Reviews
Reviews

Doug's Headers D303Y-B 1 3/4" Tri-Y Header Chevrolet Truck Big Block Chevrolet 68-87 Hi-Temp Black Coating
Doug's Headers D303Y-B 1 3/4" Tri-Y Header Chevrolet Truck Big Block Chevrolet 68-87 Hi-Temp Black Coating
Couldn't load pickup availability

Emissions Code
Continue Reading to Understand Emissions Codes
Complete Your Installation
Doug's Headers D303Y-B 1 3/4" Tri-Y Header Chevrolet Truck Big Block Chevrolet 68-87 Hi-Temp Black Coating
{{ title }}
Product Info
Product Info
- 3/8" Thick machined flanges...no warping
- CNC mandrel bent tubes... accurate fit & better flow
- Tri-Y headers yield maximum power from off idle to 4500 RPM making them well suited for applications demanding maximum mid-range torque with maximum fuel economy
- Heavy 16 gauge tubing...longer life
- Tubes are pre-polished to remove scratches and the header is finished with a Hi-Temp Black Coating
Applications and Footnotes
Chevrolet - Class A (chevrolet chassis) |
||||||||||||
EMISSION | AUTO | STD | TUBE | COLLECTOR | PORT | |||||||
YEARS | ENGINES | CODE | A/C | P/B | P/S | COL | FLR | COL | FLR | SIZE (in.) | SIZE (in.) | SHAPE |
75 - 91 | 396-502 |
|
Y | Y | Y | Y | Y | N | N | 1 3/4 - 2 | 2 1/2 | SAP |
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Carbureted applications only | ||||||||||||
Fits P30 chassis | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design | ||||||||||||
Chevrolet/GMC - GMC 2WD TRUCKS & SUV |
||||||||||||
EMISSION | AUTO | STD | TUBE | COLLECTOR | PORT | |||||||
YEARS | ENGINES | CODE | A/C | P/B | P/S | COL | FLR | COL | FLR | SIZE (in.) | SIZE (in.) | SHAPE |
68 - 87 | 396-502 |
|
Y | Y | Y | Y | Y | Y | Y | 1 3/4 - 2 | 2 1/2 | SAP |
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Big block frame stands and motor mounts must be used to insure proper engine location and header fit. | ||||||||||||
Does not fit 4 speed applications with bell housing mounts | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design | ||||||||||||
Chevrolet/GMC - 1/2, 3/4, 1 Ton / 1500, 2500, 3500 TRUCKS |
||||||||||||
EMISSION | AUTO | STD | TUBE | COLLECTOR | PORT | |||||||
YEARS | ENGINES | CODE | A/C | P/B | P/S | COL | FLR | COL | FLR | SIZE (in.) | SIZE (in.) | SHAPE |
68 - 87 | 396-502 |
|
Y | Y | Y | Y | Y | Y | Y | 1 3/4 - 2 | 2 1/2 | SAP |
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Big block frame stands and motor mounts must be used to insure proper engine location and header fit. | ||||||||||||
Does not fit 4 speed applications with bell housing mounts | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design | ||||||||||||
Chevrolet/GMC - 4 Ton / 3500 Crew, Standard Cab DUALLY |
||||||||||||
EMISSION | AUTO | STD | TUBE | COLLECTOR | PORT | |||||||
YEARS | ENGINES | CODE | A/C | P/B | P/S | COL | FLR | COL | FLR | SIZE (in.) | SIZE (in.) | SHAPE |
73 - 91 | 396-502 |
|
Y | Y | Y | Y | Y | Y | Y | 1 3/4 - 2 | 2 1/2 | SAP |
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Big block frame stands and motor mounts must be used to insure proper engine location and header fit. | ||||||||||||
Does not fit 4 speed applications with bell housing mounts | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design | ||||||||||||
Chevrolet/GMC - 8 Ton / 3500 Crew, Standard Cab DUALLY |
||||||||||||
EMISSION | AUTO | STD | TUBE | COLLECTOR | PORT | |||||||
YEARS | ENGINES | CODE | A/C | P/B | P/S | COL | FLR | COL | FLR | SIZE (in.) | SIZE (in.) | SHAPE |
73 - 91 | 396-502 |
|
Y | Y | Y | Y | Y | Y | Y | 1 3/4 - 2 | 2 1/2 | SAP |
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Big block frame stands and motor mounts must be used to insure proper engine location and header fit. | ||||||||||||
Does not fit 4 speed applications with bell housing mounts | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design | ||||||||||||
Chevrolet/GMC - Blazer / Jimmy, Suburban, Tahoe / Yukon |
||||||||||||
EMISSION | AUTO | STD | TUBE | COLLECTOR | PORT | |||||||
YEARS | ENGINES | CODE | A/C | P/B | P/S | COL | FLR | COL | FLR | SIZE (in.) | SIZE (in.) | SHAPE |
68 - 87 | 396-502 |
|
Y | Y | Y | Y | Y | Y | Y | 1 3/4 - 2 | 2 1/2 | SAP |
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Does not fit 4 speed applications with bell housing mounts | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design |
Applications and Footnotes
Chevrolet - Class A (chevrolet chassis) |
||||||||||||
YEARS | 75 - 91 | |||||||||||
ENGINES | 396-502 | |||||||||||
EMISSION CODE |
|
|||||||||||
A/C | Y | |||||||||||
P/B | Y | |||||||||||
P/S | Y | |||||||||||
AUTO COL | Y | |||||||||||
AUTO FLR | Y | |||||||||||
STD COL | N | |||||||||||
STD FLR | N | |||||||||||
TUBE SIZE (in.) | 1 3/4 - 2 | |||||||||||
COLLECTOR SIZE (in.) | 2 1/2 | |||||||||||
PORT SHAPE | SAP | |||||||||||
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Carbureted applications only | ||||||||||||
Fits P30 chassis | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design | ||||||||||||
Chevrolet/GMC - GMC 2WD TRUCKS & SUV |
||||||||||||
YEARS | 68 - 87 | |||||||||||
ENGINES | 396-502 | |||||||||||
EMISSION CODE |
|
|||||||||||
A/C | Y | |||||||||||
P/B | Y | |||||||||||
P/S | Y | |||||||||||
AUTO COL | Y | |||||||||||
AUTO FLR | Y | |||||||||||
STD COL | Y | |||||||||||
STD FLR | Y | |||||||||||
TUBE SIZE (in.) | 1 3/4 - 2 | |||||||||||
COLLECTOR SIZE (in.) | 2 1/2 | |||||||||||
PORT SHAPE | SAP | |||||||||||
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Big block frame stands and motor mounts must be used to insure proper engine location and header fit. | ||||||||||||
Does not fit 4 speed applications with bell housing mounts | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design | ||||||||||||
Chevrolet/GMC - 1/2, 3/4, 1 Ton / 1500, 2500, 3500 TRUCKS |
||||||||||||
YEARS | 68 - 87 | |||||||||||
ENGINES | 396-502 | |||||||||||
EMISSION CODE |
|
|||||||||||
A/C | Y | |||||||||||
P/B | Y | |||||||||||
P/S | Y | |||||||||||
AUTO COL | Y | |||||||||||
AUTO FLR | Y | |||||||||||
STD COL | Y | |||||||||||
STD FLR | Y | |||||||||||
TUBE SIZE (in.) | 1 3/4 - 2 | |||||||||||
COLLECTOR SIZE (in.) | 2 1/2 | |||||||||||
PORT SHAPE | SAP | |||||||||||
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Big block frame stands and motor mounts must be used to insure proper engine location and header fit. | ||||||||||||
Does not fit 4 speed applications with bell housing mounts | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design | ||||||||||||
Chevrolet/GMC - 4 Ton / 3500 Crew, Standard Cab DUALLY |
||||||||||||
YEARS | 73 - 91 | |||||||||||
ENGINES | 396-502 | |||||||||||
EMISSION CODE |
|
|||||||||||
A/C | Y | |||||||||||
P/B | Y | |||||||||||
P/S | Y | |||||||||||
AUTO COL | Y | |||||||||||
AUTO FLR | Y | |||||||||||
STD COL | Y | |||||||||||
STD FLR | Y | |||||||||||
TUBE SIZE (in.) | 1 3/4 - 2 | |||||||||||
COLLECTOR SIZE (in.) | 2 1/2 | |||||||||||
PORT SHAPE | SAP | |||||||||||
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Big block frame stands and motor mounts must be used to insure proper engine location and header fit. | ||||||||||||
Does not fit 4 speed applications with bell housing mounts | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design | ||||||||||||
Chevrolet/GMC - 8 Ton / 3500 Crew, Standard Cab DUALLY |
||||||||||||
YEARS | 73 - 91 | |||||||||||
ENGINES | 396-502 | |||||||||||
EMISSION CODE |
|
|||||||||||
A/C | Y | |||||||||||
P/B | Y | |||||||||||
P/S | Y | |||||||||||
AUTO COL | Y | |||||||||||
AUTO FLR | Y | |||||||||||
STD COL | Y | |||||||||||
STD FLR | Y | |||||||||||
TUBE SIZE (in.) | 1 3/4 - 2 | |||||||||||
COLLECTOR SIZE (in.) | 2 1/2 | |||||||||||
PORT SHAPE | SAP | |||||||||||
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Big block frame stands and motor mounts must be used to insure proper engine location and header fit. | ||||||||||||
Does not fit 4 speed applications with bell housing mounts | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design | ||||||||||||
Chevrolet/GMC - Blazer / Jimmy, Suburban, Tahoe / Yukon |
||||||||||||
YEARS | 68 - 87 | |||||||||||
ENGINES | 396-502 | |||||||||||
EMISSION CODE |
|
|||||||||||
A/C | Y | |||||||||||
P/B | Y | |||||||||||
P/S | Y | |||||||||||
AUTO COL | Y | |||||||||||
AUTO FLR | Y | |||||||||||
STD COL | Y | |||||||||||
STD FLR | Y | |||||||||||
TUBE SIZE (in.) | 1 3/4 - 2 | |||||||||||
COLLECTOR SIZE (in.) | 2 1/2 | |||||||||||
PORT SHAPE | SAP | |||||||||||
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Does not fit 4 speed applications with bell housing mounts | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design |
Highlights
Highlights
- 3/8" Thick machined flanges...no warping
- CNC mandrel bent tubes... accurate fit & better flow
- Tri-Y headers yield maximum power from off idle to 4500 RPM making them well suited for applications demanding maximum mid-range torque with maximum fuel economy
- Heavy 16 gauge tubing...longer life
- Tubes are pre-polished to remove scratches and the header is finished with a Hi-Temp Black Coating
Applications and Footnotes
Applications and Footnotes
Chevrolet - Class A (chevrolet chassis) |
||||||||||||
YEARS | 75 - 91 | |||||||||||
ENGINES | 396-502 | |||||||||||
EMISSION CODE | ||||||||||||
A/C | Y | |||||||||||
P/B | Y | |||||||||||
P/S | Y | |||||||||||
AUTO COL | Y | |||||||||||
AUTO FLR | Y | |||||||||||
STD COL | N | |||||||||||
STD FLR | N | |||||||||||
TUBE SIZE (in.) | 1 3/4 - 2 | |||||||||||
COLLECTOR SIZE (in.) | 2 1/2 | |||||||||||
PORT SHAPE | SAP | |||||||||||
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Carbureted applications only | ||||||||||||
Fits P30 chassis | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design | ||||||||||||
Chevrolet/GMC - GMC 2WD TRUCKS & SUV |
||||||||||||
YEARS | 68 - 87 | |||||||||||
ENGINES | 396-502 | |||||||||||
EMISSION CODE | ||||||||||||
A/C | Y | |||||||||||
P/B | Y | |||||||||||
P/S | Y | |||||||||||
AUTO COL | Y | |||||||||||
AUTO FLR | Y | |||||||||||
STD COL | Y | |||||||||||
STD FLR | Y | |||||||||||
TUBE SIZE (in.) | 1 3/4 - 2 | |||||||||||
COLLECTOR SIZE (in.) | 2 1/2 | |||||||||||
PORT SHAPE | SAP | |||||||||||
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Big block frame stands and motor mounts must be used to insure proper engine location and header fit. | ||||||||||||
Does not fit 4 speed applications with bell housing mounts | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design | ||||||||||||
Chevrolet/GMC - 1/2, 3/4, 1 Ton / 1500, 2500, 3500 TRUCKS |
||||||||||||
YEARS | 68 - 87 | |||||||||||
ENGINES | 396-502 | |||||||||||
EMISSION CODE | ||||||||||||
A/C | Y | |||||||||||
P/B | Y | |||||||||||
P/S | Y | |||||||||||
AUTO COL | Y | |||||||||||
AUTO FLR | Y | |||||||||||
STD COL | Y | |||||||||||
STD FLR | Y | |||||||||||
TUBE SIZE (in.) | 1 3/4 - 2 | |||||||||||
COLLECTOR SIZE (in.) | 2 1/2 | |||||||||||
PORT SHAPE | SAP | |||||||||||
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Big block frame stands and motor mounts must be used to insure proper engine location and header fit. | ||||||||||||
Does not fit 4 speed applications with bell housing mounts | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design | ||||||||||||
Chevrolet/GMC - 4 Ton / 3500 Crew, Standard Cab DUALLY |
||||||||||||
YEARS | 73 - 91 | |||||||||||
ENGINES | 396-502 | |||||||||||
EMISSION CODE | ||||||||||||
A/C | Y | |||||||||||
P/B | Y | |||||||||||
P/S | Y | |||||||||||
AUTO COL | Y | |||||||||||
AUTO FLR | Y | |||||||||||
STD COL | Y | |||||||||||
STD FLR | Y | |||||||||||
TUBE SIZE (in.) | 1 3/4 - 2 | |||||||||||
COLLECTOR SIZE (in.) | 2 1/2 | |||||||||||
PORT SHAPE | SAP | |||||||||||
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Big block frame stands and motor mounts must be used to insure proper engine location and header fit. | ||||||||||||
Does not fit 4 speed applications with bell housing mounts | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design | ||||||||||||
Chevrolet/GMC - 8 Ton / 3500 Crew, Standard Cab DUALLY |
||||||||||||
YEARS | 73 - 91 | |||||||||||
ENGINES | 396-502 | |||||||||||
EMISSION CODE | ||||||||||||
A/C | Y | |||||||||||
P/B | Y | |||||||||||
P/S | Y | |||||||||||
AUTO COL | Y | |||||||||||
AUTO FLR | Y | |||||||||||
STD COL | Y | |||||||||||
STD FLR | Y | |||||||||||
TUBE SIZE (in.) | 1 3/4 - 2 | |||||||||||
COLLECTOR SIZE (in.) | 2 1/2 | |||||||||||
PORT SHAPE | SAP | |||||||||||
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Big block frame stands and motor mounts must be used to insure proper engine location and header fit. | ||||||||||||
Does not fit 4 speed applications with bell housing mounts | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design | ||||||||||||
Chevrolet/GMC - Blazer / Jimmy, Suburban, Tahoe / Yukon |
||||||||||||
YEARS | 68 - 87 | |||||||||||
ENGINES | 396-502 | |||||||||||
EMISSION CODE | ||||||||||||
A/C | Y | |||||||||||
P/B | Y | |||||||||||
P/S | Y | |||||||||||
AUTO COL | Y | |||||||||||
AUTO FLR | Y | |||||||||||
STD COL | Y | |||||||||||
STD FLR | Y | |||||||||||
TUBE SIZE (in.) | 1 3/4 - 2 | |||||||||||
COLLECTOR SIZE (in.) | 2 1/2 | |||||||||||
PORT SHAPE | SAP | |||||||||||
Available with optional smog pump provision. Dual smog pump applications add DP to the end of header part number. Single smog pump applications add SP to end of header part number | ||||||||||||
Does not fit 4 speed applications with bell housing mounts | ||||||||||||
Non catalytic converter equipped. | ||||||||||||
Tri-Y design |
Additional Information
Additional Information
Doug's 2/4 WD TRUCK HEADERS Tri-Y Hi-Temp Black Coated Header development and design is complex and requires a substantial amount of time and resources to do the job right! Many manufacturers are unwilling to make the commitment and instead offer compromised headers at lower prices. Doug's will not compromise performance, quality or fit to compete with inferior designs at cheap prices. Every Doug's header is tuned with the proper tube size and length to efficiently remove all the exhaust from each cylinder, reducing pumping losses resulting in a dramatic increases in horsepower and torque. Doug's headers are carefully developed on the vehicles they are intended to fit and are re-checked numerous times during the design and manufacturing process.
Download instruction manual
Download instruction manual
Reviews
Reviews

EMISSIONS PLACARD
PerTronix Performance Ignition and Exhaust Brands use a voluntary product identification program whereby all emission sensitive products can be identified by placing numbered labels in product packaging and listing corresponding numeric codes next to each part number. The corresponding numbers and explanations are as follows:

PERTRONIX PERFORMANCE BRANDS EMISSIONS CODES
This product has been granted a California Air Resources Board (CARB) Executive Order (EO Number) Exemption. It is 50 State Legal when installed on the Specified vehicle per the Manufacturer’s Current Application Guide, the CARB EO, and Installation Instructions.

PERTRONIX PERFORMANCE BRANDS EMISSIONS CODES
This product is Legal for use on Pre-PoIIution Controlled Vehicles. It is legal for use on all vehicles produced Before Emissions Control Regulations were imposed. These are considered Uncontrolled Vehicles and are defined as follows
- 1965 and Older US Manufactured California Certified Vehicles
- 1967 and Older US Manufactured Federally Certified Vehicles
- 1967 and Older Foreign Manufactured Vehicles

PERTRONIX PERFORMANCE BRANDS EMISSIONS CODES
This Product is LEGAL for Closed Course Competition use or Pre-Emissions Controlled Vehicles ONLY. It is Not Legal for use on any Emissions Controlled Vehicle for Street or Off Highway use.

PERTRONIX PERFORMANCE BRANDS EMISSIONS CODES
This Product is considered а Replacement Part per CARB and EPA regulations for emissions compliance and is legal for sale and use on specified vehicles in all 50 states as stated in Manufactured's Application Guide and lnstallation Instructions.

PERTRONIX PERFORMANCE BRANDS EMISSIONS CODES
This Product is legal for Street or Off Highway use in 49 States. This product meets the EPA Anti Tampering Policy for Reasonable Basis that allows the stated vehicle to operate within the legal emissions standards in states that do not require а California EO. This product in Not Legal for Street or Off Highway use in California.

PERTRONIX PERFORMANCE BRANDS EMISSIONS CODES
This Product is Certified by the Manufacturer as being а Non-Emissions Related part per CARB and EPA regulations and therefore does not require emissions certification or CARB EO and is legal in all 50 states.
You may also like
Disclaimer
Please select the applicable intended choice of installation:
- 1965 and Older US Manufactured California Certified Vehicles
- 1967 and Older US Manufactured Federally Certified Vehicles
- 1967 and Older Foreign Manufactured Vehicles
- 1966 and newer US Manufactured California Certified Vehicles
- 1968 and newer US Manufactured Federally Certified Vehicles registered
- 1968 and newer Foreign Manufactured Vehicles
We cannot sell this part for use on this vehicle. It will not be added to your cart. Click the button below to close the window and return to the product page.
Federal and state "anti-tampering" laws regulate modifications that affect emissions from motor vehicles and prohibit the sale, installation, and on-highway use of any add-on or modified emissions-related part on any pollution-controlled vehicle unless the part has received an exemption from the California Air Resources Board ("CARB"), is considered an exempt or replacement part, or we as the manufacturer have reasonable basis to know that the part does not increase emissions above the applicable standard in compliance with the EPA tampering policy. If a part has a California Executive Order Exemption (EO #) or meets the requirements for an exempt part such as a Cat Back Exhaust system or is considered a replacement part, it is legal for sale or use in all 50 states. If a part is compliant with EPA’s tampering policy, it is legal for sale or use in all states except California. We are required by law to inform you about the legality of parts that we manufacture and sell and will refuse the sale of certain parts if the following requirements are not conformed with. Use of non-compliant parts for purposes other than stated can result in a citation, fines, or the inability to register the vehicle. For the product you are attempting to add to your cart, you must certify, by clicking one of these boxes that you are using the product in the manner stated and for the application as specified by the manufacturer.
Disclaimer
Some parts are not legal for use in California or other states with similar laws/regulations regarding emissions.