How much does it matter if the primary ports on headers match the exhaust ports on the heads.

Are headers with D shaped primary ports better than headers with Oval shaped ones?

And If so how much better/worse?

Does the D port gasket restrict Oval port primarys?

Example: Rk Sport Mids and AS&M mids other than the coating the only difference in these are the port types AS&M is D shaped and RK's are Oval. Does it matter performance wise?

Thanks

-Dustin-

 

The LT1 heads use D type ports, Although they would probobaly seal, I wouldn't use oval port headers on them.

 

As long as the header openings don't cover any of the port in the head, it should be good. Header openings which are bigger than the port, especially at the bottom of the port, help prevent reversion or reverse flow of the exhaust gas back into the cylinders. This is a good thing.

 

So those headers with Ovals are ok to get? Performance wise? So RK's are about the same as the AS&M as long as you dont mind the coating?

-Dustin-

 

Yes.

They are both great headers from what I've researched.

Dan

 

I am just using these as examples, I change my mind on headers daily. Today I want JetHot LT's

-Dustin-