head flow

Your question is very general. You'll need to post all the specs about your engine that you can. In general (very) a head (or engine combo) being pushed has the abilty to produce the CFM X's 2 for HP or more. 286 x 2 = 572 HP this is potential and will only work when you put the screws to the build. A milder cam, compression ratio, sub par intake, to small of a carb, the list goes on and on. But these things will make and break the possible out come for any build, even more so when you try and make the CFM C's 2 work for you.