I was wondering if all headers come with a round pipe at the flange to the head, or if someone makes them to match the "D" shaped port on the stock LT1 head?
roadgod

 

Can't remember, however its the flange that is shaped, not the primary. I would guess that the flange on my SLPs are D shaped, I know that the gaskets I bought are D shaped. JMHO

 

I'm pretty sure the flange on my pacesetters was D-shaped.

 

Header flanges tend to be an oval or rounded rectangle shape.
I never did quite understand why they would not match the head exhaust port.

EDIT: Here is a pic of my 1-3/4" LT1 Hooker/JetHot Headers fresh off of my car.

 

LT1 header flanges do have D-Ports. Gen I motors have the oval ports. I have an LT1 in my 91 camaro and since they don't make any 1 3/4 LTs(only 1 5/8) with D-Ports, I had to use Gen I hooker headers. From what Ive read though, since the flange is so close to the port, the exhaust gas is still expanding so the step down doesn't effect it much.