AFR Heads
Yeah, something like that. On 340-360 inches (depending on how you get there) a head like that will make power (on gasoline) it will make power to 8800-9000 rpm and a shift rpm of 500-700 rpm above that.
On alcohol you can drop that by a minimum of 500 rpm.
370-390 inches you will struggle to make power above 8200ish on gasoline. You can push it higher but you most likely will be soggy at the bottom of the gear changes and you’ll have to zing it up higher to get it to move. Alcohol will lower the rpm like above.
Anything over 390 inches and you just can’t get the area to make power very high. It’s a waste of time IMO to do it. You just give up too much rpm to make it worth while.
And I should add that’s with a tunnel ram that’s fully ported. A single 4 changes those numbers.