Pontiac 421/455SD Super Duty D-Port Stainless Header Flange

Precision laser cut from 3/8" thick 304 Stainless Steel, our header flanges are manufactured in the U.S. and are machine surfaced. These header flanges are specifically made for the Super Duty V8 Pontiac heads, 421 + 455 CID. They feature the same bolt pattern and port location as stock Pontiac V8 D-Port heads, but with larger exhaust ports, and more clearance around the flange.

Port Size: 1.880"

Preformed Flange Stubs are 2"-3" in length, and are formed to perfectly fit the non-round port in the flange. Stubs drastically reduce overall build time and increase builder's efficiency.

We carry over 450 different header flange designs, so if you don't see the flange you're looking for, talk with one our tech reps about custom header flange cutting.

Flanges sold separately.