kgkern01

iTrader: (10)

I've always wondered how these two situations compare. What effects do larger heads have with respect to the power curve given the same cam? For example, ported heads or larger factory heads given the same cam and engine? Or even the effect of going larger on the heads with a small cam? The reason I ask is that when having to say replace a head gasket, would it not be worth it to go ahead and put better heads on it, for future cam install? I see these new LS style engines coming out from the factory with big heads on them, so I would assume there is some power to be had with big heads/small cam as well?

Steve Bryant

iTrader: (1)

In my opinion, neither is a very good combination. A small duration cam will have good torque and power with a small intake runner head that flows well at low and mid lift regions and has respectable numbers between .5: and .6" lift. This kind of setup is great for a daily driver road racing car. A big (longer duration higher lift) cam will work best with heads with larger volume intake runners that flow really well in the mid to high lift region. These heads will mostly be suited to peak power and ill-suited to part throttle operation (i.e. mainly a race only dragster). In all cases, the exhaust flows should be proportionate to the intakes (say around 70% at a given lift).

A big cam with a small head will stall out or become turbulent at high lifts and this is counterproductive. A small cam with a big head never reaches the potential and the single minded purpose of that type of head.

That's my two cents on the subject.

Steve

One last thought. Great heads with a good cam is a better combination than good heads with a great cam.