318 head flow

^^^ You are right on all accounts.
I have gotten 236 out of a lesser worked 360 head with 1.88 valve, and have hit low 280s with a "max effort" port job. You are also correct that the bowl is under sized, after a little probing with the sonic checker, they are as thin as I care to go. This whole 318 deal is just for ***** and giggles, science experiment is an accurate description though.