i found my notes on when i freshened up the EM470 heads for 440Jim.
this is what i would consider a couple of the better overall ports on that set of heads(the highest flowing intake port didnt have the best area under the curve, but did flow 365.7 @ .700 lift).
keep in mind this is also a 30cc+/- smaller port than the Chapman 285's, and we didnt have the luxury of the longer valve, added roof height, or added short turn height to play with.
all in all.....i think if we had some of these same bare castings that Chapman had, and MD did another port design similar to the ones on the EM470 heads....it might even flow more than the Chapman 285's...with the same, or smaller, runner volume.
i dont think i had my 4.375 bore adapter when i got these last numbers, so on the bigger bore, the mid-lift numbers on the EM heads might be even better.
it'll be interesting to see how the Chapman 260's compare to the EM470 heads, since the runner volumes are closer to each other.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
