D shaped exhaust port

[Barbadian Camaro]

Hi guys not really sure if I am posting in the right section this is for 3.4L head upgrade,but I was doing quite a bit of reading on the aluminium head conversions especially the head with the D shape ports,and I did not see no one mention on what Headers they use with the D shaped head,because the 70-1208 pacesetter header is round port.

[landj]

Re: D shaped exhaust port

I hadn't done it, but I too was curious. I looked Russell's bible (black34v6's writeup that's stickied) and it seems to me from my reading that the 3.4 RWD headers bolt right up to the 3400 heads. Perhaps the loss of velocity from the turbulence of the shape mismatch is so little compared to the gain of the swap??? I thought I remember someone saying that there is a slight difference but it doesn't matter, but I couldn't find that quoted...

Hopefully someone who's done it can chime in...

[Opontee]

Re: D shaped exhaust port

Just about every american made v-8 race engine has d-port exhaust and almost all of them use round port headers. I know for a fact that my dad's 500" BBC's have d-port heads and round port headers.

[Barbadian Camaro]

Re: D shaped exhaust port

Ok thanks for the input and or info,but it had crossed my mind being if they will be any restriction knowing you cannot get a good flow when round matched to square if the round is slightly smaller to the square,hence the phrase "Matched Port".