But my overall point is we're building Mopars and we really don't have huge port heads and if the Cleveland guys can get away using 4V heads on 302-351 I'm sure we don't have to worry as much as people do.
Especially people worry about port velocity but seems like not many know how much velocity you need and what port size to cfm to get there, but IF these formulas have any accuracy we seem to suffer from not enough port volume.
Eg.. Recommended ideal velocity is average csa that gives you 260 fps with desired cfm, so say 260 cfm x 2.4 / 260 fps = 2.40" average csa, if the average port length is around 4.95" which Earlie A measured SM port to be that's a port volume of 195 cc we would consider that a vary large port for only 260 cfm, we would hope to get more like 300 cfm out of that port volume which would increase port velocity to 300 fps.
You would have to get like only 225 cfms out of a 195 cc port to get a low velocity like 225 fps which is pretty unrealistic scenario and a velocity of 225 fps is still considered board line usable.
Even a 200 cfm say for a mild 318 = 150 cc for a 260 fps basically a stock 360 head. Seems like we might have not enough volume problem, or put another way too much velocity.