Doug's Headers - D521

Doug's Headers D521 1 3/4" 4-Tube Full Length Header Pontiac Catalina 326-455 65-68 Metallic Ceramic Coating

Doug's Headers D521 1 3/4" 4-Tube Full Length Header Pontiac Catalina 326-455 65-68 Metallic Ceramic Coating

Part Number: D521 / UPC 694342509767
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Highlights

  • 3/8" Thick machined flanges... no warping
  • CNC mandrel bent tubes... accurate fit & better flow
  • Precision formed long transition collectors and long tube design... reduces backpressure and increases higher RPM horsepower
  • Heavy 16 gauge tubing... longer life
  • Tubes are pre-polished to remove scratches and the header is finished with a Metallic Ceramic Thermal Barrier Coating polished to a high luster appearance offering corrosion and heat resistance up to 1400 degrees

Additional Information

Doug's PASSENGER CAR HEADERS Long Tube Metallic Ceramic 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.

Installation instructions

Instruction Manual
Installation Instructions

Download PDF

Shipping & Delivery

Our ignition and exhaust products ship from our warehouse in Lenexa, KS. Our normal shipping time is 2-3 business days for in-stock parts.

 Shipping Class Order Value Shipping Cost
UPS Ground $0 - 49.99 $6.99 flat rate
UPS Ground $50 - 98.99 $7.49 flat rate
UPS Ground $99+ Free

  • At this time, PerTronix does not offer expedited shipping options from our website.
  • All packages must be inspected upon receipt for any missing or damaged goods and claims for such must be made within 7 days of receipt.
  • PerTronix does not currently ship our products internationally from our web store. For international orders call 909-599-5955 or connect with us here.

Returns & Replacements

Returns at Pertronix are accepted within 90 days of purchase with prior authorization, ensuring items are in new, resalable condition. To initiate a return, call for an RGA and follow provided instructions. Customers are responsible for return shipping, using a trackable method.

Refunds exclude initial shipping and handling fees and may be subject to a restocking fee. For defective or damaged items, contact Pertronix directly. We are not responsible for user-initiated damage/loss of parts.

For complete details, visit our Returns page.

Reviews

Doug's Headers - D521

Doug's Headers D521 1 3/4" 4-Tube Full Length Header Pontiac Catalina 326-455 65-68 Metallic Ceramic Coating

Doug's Headers D521 1 3/4" 4-Tube Full Length Header Pontiac Catalina 326-455 65-68 Metallic Ceramic Coating

Part Number: D521 / UPC 694342509767
Regular price $1,109.95
Sale price $1,109.95 Regular price

Part Number: D521 / UPC 694342509767
View All Vehicle Applications

Need help? Call us at 909-599-5955

  • Free shipping on $99+ orders in lower 48 states
  • 90-day return policy
  • We’re here to help! Call us on 909-599-5955
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Highlights

  • 3/8" Thick machined flanges... no warping
  • CNC mandrel bent tubes... accurate fit & better flow
  • Precision formed long transition collectors and long tube design... reduces backpressure and increases higher RPM horsepower
  • Heavy 16 gauge tubing... longer life
  • Tubes are pre-polished to remove scratches and the header is finished with a Metallic Ceramic Thermal Barrier Coating polished to a high luster appearance offering corrosion and heat resistance up to 1400 degrees

Additional Information

Doug's PASSENGER CAR HEADERS Long Tube Metallic Ceramic 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.

Installation instructions

Instruction Manual
Installation Instructions

Download PDF

Shipping & Delivery

Our ignition and exhaust products ship from our warehouse in Lenexa, KS. Our normal shipping time is 2-3 business days for in-stock parts.

 Shipping Class Order Value Shipping Cost
UPS Ground $0 - 49.99 $6.99 flat rate
UPS Ground $50 - 98.99 $7.49 flat rate
UPS Ground $99+ Free

  • At this time, PerTronix does not offer expedited shipping options from our website.
  • All packages must be inspected upon receipt for any missing or damaged goods and claims for such must be made within 7 days of receipt.
  • PerTronix does not currently ship our products internationally from our web store. For international orders call 909-599-5955 or connect with us here.

Returns & Replacements

Returns at Pertronix are accepted within 90 days of purchase with prior authorization, ensuring items are in new, resalable condition. To initiate a return, call for an RGA and follow provided instructions. Customers are responsible for return shipping, using a trackable method.

Refunds exclude initial shipping and handling fees and may be subject to a restocking fee. For defective or damaged items, contact Pertronix directly. We are not responsible for user-initiated damage/loss of parts.

For complete details, visit our Returns page.

Reviews

Applications

Year / Make / Model 1965-1966 Pontiac Bonneville
Engine Type V8
Engine Size(s) Cubic Inches: 389, 421
Notes
  • Fits D-Port heads Only.
  • Some factory heads do not have end bolt holes and should be drilled and tapped to assure proper sealing.

Year / Make / Model 1967-1968 Pontiac Bonneville
Engine Type V8
Engine Size(s) Cubic Inches: 400, 428
Notes
  • Fits D-Port heads Only.
  • Some factory heads do not have end bolt holes and should be drilled and tapped to assure proper sealing.

Year / Make / Model 1965-1966 Pontiac Catalina
Engine Type V8
Engine Size(s) Cubic Inches: 389, 421
Notes
  • Fits D-Port heads Only.
  • Some factory heads do not have end bolt holes and should be drilled and tapped to assure proper sealing.

Year / Make / Model 1967-1968 Pontiac Catalina
Engine Type V8
Engine Size(s) Cubic Inches: 400, 428
Notes
  • Fits D-Port heads Only.
  • Some factory heads do not have end bolt holes and should be drilled and tapped to assure proper sealing.

Year / Make / Model 1965-1966 Pontiac Grand Prix
Engine Type V8
Engine Size(s) Cubic Inches: 389, 421
Notes
  • Fits D-Port heads Only.
  • Some factory heads do not have end bolt holes and should be drilled and tapped to assure proper sealing.

Year / Make / Model 1967-1968 Pontiac Grand Prix
Engine Type V8
Engine Size(s) Cubic Inches: 400, 428
Notes
  • Fits D-Port heads Only.
  • Some factory heads do not have end bolt holes and should be drilled and tapped to assure proper sealing.

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