Velocity is important but it's only one of many things that's important.
318 heads are basically 273 heads which were designed for 273 displacement with near zero performance in mind, it's amazing they work as well as they do. There's 45 cid difference between 273 and 318 only 22 cid difference between 318 and 340 less after and 0.030-0.060" overbore 323-328 12-17.
2.02 X heads were designed to work with a mild 340 in mind, 360 came with overly restricted heads compared to the 340 head flow to cid ratio which the 273 has similar ratio, why there both considered revving engines, a 360 would need a set of edelbrock's to maintain the same ratio and 318 a set of 1.88 360 heads.i understand performance and mods...but the 318s is a very différent animal
People confuse strangling their engine with making tq.
Once you do the basic 4bbl rv cam headers and good tune that's basically all the under 3000 rpm tq your gonna have. The trick is to move/extend the rpm range from idle to 4000/4500 rpm a truck power curve to 5000/5500 rpm decent performance engine without losing too driveability in the driving speeds of idle-2500 rpm. Now with more gear and stall this rpm range matters less.
NA Power mostly boils down to cam and heads. And cam is a relatively narrow choice on the street, especially if streetability is a more primary concern I'd say depending on the cam you could go up to 212 cam in a 318 without losing anything any real notice downstairs, around 220-225 you start trading bottom for top end.
So say you decide on a 215 cam then heads are gonna be the deciding factor in power, stock 318 heads = 275 hp, 360 heads = 325 hp guesstimated if done reasonably right.
A 325 hp stock 318 head engine probability gonna need at least another 20 degrees of cam timing which would be way less streetable than any loss to velocity.
It's all a series of compromises.
