> NECESSARILY MAKE MORE HORSEPOWER.
When I was putting my engine specs together, I had head flow numbers and
cross-sectional areas from several sets of heads I had personally put on
a flow bench, as well as independent flow numbers from other people's heads
and CHI's claimed (also from another source) numbers. When I ran them
through Dynomation (a high end simulation package), using actual dimensions
for everything, my C302B's made the best power (peak and average) in the RPM
range I'm interested in, followed closely by my A3's and spare C302's and
then by the Brodix BF300's and CHI 3V's. Stock 4V's were way behind and the
Edelbrock Performer 2V's were even worse. If I had bowl ported the A3's,
I'd bet they would have made more than the C302B's. Understand this isn't
an apples-to-apples comparison given the different levels of porting and
the results would likely be different on a different engine. There are also
limitations to simulation program. It can not predict the effect of the
chamber shape on swirl and tumble, for instance. That said, the important
things (to the program at least) are the flow average within the lift range
of the cam chosen (some heads like the Blue Thunder flowed better at higher
lifts but made less power due to the cam chosen, with a bigger lift solid
roller and more compression those results would likely change), the ratio
of intake-to-exhaust flow (Smokey Yunick's porting experiment holds here),
intake tract speed (there's a flow speed that's best and larger port volumes
can sometimes make better power than a head with smaller port volumes and
the same flow numbers), as well as how well the rest of the engine parameters
(bore, stroke, compression ratio, intake and exhaust dimensions, cam timing,
etc.) suit the heads.
> I hear voices in my head you know. The problem is I don't know what they are
> saying. They are in a foreign language. (And you thought you were crazy huh?)
Dan Jones