Quote:
Originally Posted by Mike Mans
There are a whole lot of variables that you would have to define, but here's a basic rule of thumb from a cylinder head perspective:
HP/2.25 = Peak CFM per runner on a Stock/Super Stock style engine. A decent engine in this world will make 2.25hp/cfm of head flow. Really efficient engines surpass it, and lesser refined motors may be a little lower. But this should get you in the ballpark.
So if you want enough head to support 650hp, you'll need around 285-290cfm of peak flow to get you there pretty easily. The big thing you need to figure out is at what peak RPM you want to make this 650hp  |
Is this a Super Stock engine?
If not, what are the limits or restrictions?
If no Restrictions, The valve size, valve lift, RPM, compression, Intake type, carb size all come into play as well.
A good aftermarket head (23 degree)that will flow approximately 310 to 320 CFM and a runner volume min. 190 with a single 4 bbl carb should get you into the ball park. Just my opinion, camshaft selection will have a large influence also. Less restrictions give you some leeway in getting to that 650 HP figure.
Respectfully,
Henry Kunz 1534 Stock