Head question??

there's still plenty of air speed, maybe not the same fps...but it's moving fast, i think the diff between keeping it ''stirred'' and ''fuel drop out'' might be confused here, on a running engine the ports are indeed wet, no matter how much velocity/air speed there is....if the fuel dropped out...the engine would possibly flood or foul plugs...on top of running flat on the bottom.

as for standard replacement head gaskets...well the standard replacement is a 8553 perma torque with a 4.180 bore and crushed measures .045.
The felpro thats .039 thick 'compressed' is the 10.5 comp and up rac head gasket.
can u get them with diff bores and crushed thickness? heck yeah u can...it's just not the over the counter 'standard replace' stuff.

as for port 'STOCK' volume, the 318 heads measure 124cc int port...and the 360 LA heads measure 160cc w/1.88 and 155cc with 2.02.....the reason for the smaller port volume w/bigger valve is due to the larger under head tulip on the 2.02 that eats up bowl volume. If you go with after market valves, its a diff story and the reverse of which one has more.

so u basically have a 31-36cc port volume increase when going to the factory LA 360 heads.

Yes, it is true that 'to a point' you want the most air flow going through the smallest hole/port u can get.....that is...till the rpm's vs cid gets too big....then the small port can kick rocks. lol

other things to consider if/when gong to the larger port ontop of the 318, is...that a carb on the smaller side 'rpm's in mind' will mix even better at low rpms/off idle 'though rpm torque is limited '...simply cause of the smaller hole/air speed bit...and hey, we all know where the fuel is supposed to be mixed 'the carburetor'

which would I rather have on a 55-6000 rpm 318 with ur average 280* or less cam, the 360 heads or ported 318 heads that flow the same?

I would take the ported 318 head.

those r my thoughts on this.