Doug's Headers are a fixture in the motorsports aftermarket, pioneering quality muscle car performance headers for decades. Unlike the competition, Doug's Headers prides ourselves on superior design detail resulting in a hassle-free installation for any application.
| Download Name | File Size |
| D521.pdf | 325.18KB |
| D521-B.pdf | 325.18KB |
| Make | Model | Years | Engine | Fitment Notes |
| Pontiac | Bonneville | 1965 | 6.9L / 421 / V8 6.4L / 389 / V8 |
Fits D-Port heads Only. Some factory heads do not have end bolt holes and should be drilled and tapped to assure proper sealing. Full-length with Floor Shifter |
| Pontiac | Bonneville | 1966 | 6.9L / 421 / V8 6.4L / 389 / V8 |
Fits D-Port heads Only. Some factory heads do not have end bolt holes and should be drilled and tapped to assure proper sealing. Full-length with Floor Shifter |
| Pontiac | Bonneville | 1967 | 7.0L / 428 / V8 6.6L / 400 / V8 |
Fits D-Port heads Only. Some factory heads do not have end bolt holes and should be drilled and tapped to assure proper sealing. Full-length with Floor Shifter |
| Pontiac | Bonneville | 1968 | 7.0L / 428 / V8 6.6L / 400 / V8 |
Fits D-Port heads Only. Some factory heads do not have end bolt holes and should be drilled and tapped to assure proper sealing. Full-length with Floor Shifter |
| Pontiac | Catalina | 1965 | 6.9L / 421 / V8 6.4L / 389 / V8 |
Fits D-Port heads Only. Some factory heads do not have end bolt holes and should be drilled and tapped to assure proper sealing. Full-length with Floor Shifter |
| Pontiac | Catalina | 1966 | 6.9L / 421 / V8 6.4L / 389 / V8 |
Fits D-Port heads Only. Some factory heads do not have end bolt holes and should be drilled and tapped to assure proper sealing. Full-length with Floor Shifter |
| Pontiac | Catalina | 1967 | 7.0L / 428 / V8 6.6L / 400 / V8 |
Fits D-Port heads Only. Some factory heads do not have end bolt holes and should be drilled and tapped to assure proper sealing. Full-length with Floor Shifter |
| Pontiac | Catalina | 1968 | 7.0L / 428 / V8 6.6L / 400 / V8 |
Fits D-Port heads Only. Some factory heads do not have end bolt holes and should be drilled and tapped to assure proper sealing. Full-length with Floor Shifter |
| Pontiac | Grand Prix | 1965 | 6.9L / 421 / V8 6.4L / 389 / V8 |
Fits D-Port heads Only. Some factory heads do not have end bolt holes and should be drilled and tapped to assure proper sealing. Full-length with Floor Shifter |
| Pontiac | Grand Prix | 1966 | 6.9L / 421 / V8 6.4L / 389 / V8 |
Fits D-Port heads Only. Some factory heads do not have end bolt holes and should be drilled and tapped to assure proper sealing. Full-length with Floor Shifter |
| Pontiac | Grand Prix | 1967 | 7.0L / 428 / V8 6.6L / 400 / V8 |
Fits D-Port heads Only. Some factory heads do not have end bolt holes and should be drilled and tapped to assure proper sealing. Full-length with Floor Shifter |
| Pontiac | Grand Prix | 1968 | 7.0L / 428 / V8 6.6L / 400 / V8 |
Fits D-Port heads Only. Some factory heads do not have end bolt holes and should be drilled and tapped to assure proper sealing. Full-length with Floor Shifter |
| Collector Attachment | 3-Bolt Flange |
| Collector Diameter | 3.0 IN |
| Collector Port Diameter | 3.0 IN |
| Cylinder Head Port Shape | D-PORT |
| Design | Full-length |
| Flange Thickness | 0.375 IN |
| Gasket Or Seal Included | Yes |
| Gaskets Included | Yes |
| Grade Type | Performance |
| Header Style | Full-length |
| Mounting Hardware Included | Yes |
| Oxygen Sensor Port | No |
| Part Type | Exhaust Header |
| Port Shape | D-Port |
| Primary Tube Outside Diameter | 1.75 IN |
| Proposition 65 | www.P65Warnings.ca.gov |
| Tube Wall Thickness | 16 GU |
| Warranty Time | 24 Months |
