Quote:
Originally Posted by F/S GTO
Wrap your head around this. My 350 HO shows 450 hp on the Moroso speed power calculator. The heads flow 200 c.f.m . Of course that's Stock and not SS. My head was the one poured by NHRA for the spec on their website for the 18 head.
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Yeah, that's interesting.
If I remember correctly, he ran high 10's with that engine, in his '68 Bird.
I wonder how much power is possible with that same 200cfm flow, for a 400, a 428, or a 455 engine, with the correct cam for head flow & engine used ?
Also the heads used on the larger 4-barrel engines would have bigger valves, or at least bigger intake valves.
I'm just ASSUMING that if those heads would make 450hp, on a 350, with a low lift Stocker cam, they would have to make more than 450hp on a larger cube engine, with a bigger cam, wouldn't they ? OR, would the 200cfm flow actually limit the power of the larger cube engines, so that they couldn't make any more power than the 350 ?
I have all these questions because I really don't have a clue. Exactly how much torque & hp can be made with a 400, 428, & 455 engine, with heads that flow 200cfm, 210cfm, 220 cfm. I'd love to have the money to do all the dyno testing to find out, for sure.
Anybody here have a Pontiac engine that made over 450hp, with unported D-port iron heads ? Not counting the Stock Elim cars.
Len Williams estimates that his 6X head 455 will make aprox 425hp. That's with unported heads, and at aprox 9.25 pump gas CR. It has Rhoads lifters & what i assume is probably an 041 clone cam, like maybe a Melling SPC-8.
http://lenwilliamsautomachine.com/455_Long_Block.html
If that estimate is pretty close, then, with the correct drag only cam, it should easily make over 450hp. How much over, I don't know.