Reply to "Cylinder head identification."

> So your smaller port C3's outflow the larger port B and A's Dan?

My A3's were 327/234, the C302B's were 331/230, and the C302's
were 318/242 CFM. All were tested on the same bench, same day, and
same test conditions. I sold the B351's before I got a chance to
test them but the guy I bought them said they were 320+ CFM on the
intake side. The A3's were essentially unported, having only a
cartridge roll clean up. The C302's and C302B's were both ported
but by no means maxxed out. With a good bowl blending and valve
job, the A3's should do much better. I've seen numbers in the 360+
CFM range for both A3's and C302B's and a local Pantera owner has
a set of C302B's that supposedly pull 350 CFM. In my Dynomation
simulations, the C302B's were best but only a few HP separated
them from the C302's and the unported C302B's. I also ran the same
simulations using Kelly Coffield's Brodix BF300 flow numbers and
dimensional info, as well as the flow data for a set of 218 cc CHI
3V's. Kelly's heads were essentially unported and fitted with
smaller 2.135" intake valves but pulled 325/213 CFM (243 with a
pipe on the exhaust side). However, if you compare his numbers to
my C302B numbers, the unported BF300 heads took 0.1" more lift to
reach similar flow values so the area under the curve is less.
The same situation held for the CHI 3V heads (my C302B's flowed
more at 0.6" lift than the CHI 3V's at 0.7"). This was reflected
in the Dynomation power predictions as both the CHI 3V and unported
Brodix BF300 were down 35-50 HP. Understand this is an apples to
oranges comparison since all the heads had differing levels of
preparation, some were tested on different benches under different
conditions and the simulation can't account for differing chamber
designs (swirl/tumble, etc.). Kelly has had his engine on the dyno.
I should try to get all the particulars and see how well Dynomation
replicates the results. We got a pretty good match for my
buddies 556 HP 418W.

Dan Jones