[Gach]

Originally Posted by steve25

Factory iron D ports can be ported to go 290 intake cfm at less then 190 CCs , so why is it so hard to believe that aftermarket aluminum D ports can go 330 when they start off at atleast 188 CCs if not 200?

I wasn’t going to get into this, but I just can’t let this statement go. Maybe on your flow bench. LOL

A lot of emphasis on flow numbers, which dose mean something but not a hell of allot. What it really boils down to when it comes to a d-port vs round port is what your goal and what your intentions are with a Car.

Yeah maybe can get 290 cfm on iron d-Port, but whats the air speed in the port. Just a little example a set of wide ports done by well known Pontiac engine builder when checked ( because he was very disappointed) in the performance was you ready 425 fps. Finally after going to a guy Who has one of the best reputations, he ended up dropping it to 325 fps. Car pick up a tremendous amount of power. There’s allot more it then air speed in port. But just goes to show how much flow number only matter if its a good port.

Oh yeah of course when he drop the air speed the flow numbers drop also, but he pick up 75 hp.