Quote:
Originally Posted by SRH916
Still a tiny bit confused, let me see if I got it right, the heads are a choke point here?
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Yep, as noted in my post
"the heads are still the limiting factor".
Bottom line is that it doesn't do any good to have more lift than the head will flow - if flow tops out at .400, then going much beyond that doesn't buy much. We can add duration to make up for topping out the flow (leaving the valves open LONGER since it doesn't do any good to open them FURTHER, but that diminishes pretty quick as well and since it typically comes with more overlap there are some sacrifices in driveability and fuel economy - more than you'd typically see for a properly designed engine making the same power levels. Once you hit the wall on the cam, upgrading the heads is the only real option.
Swap some Vortecs onto that 250 horse with a cam upgrade and headers and you're into 325+ HP...