AJ's Opinion; Just for you 318 streeters

318 stock or stock rebuild with a 340 cam and some 920 style heads , headers and performer intake/carb is a nice street motor. Especially in a 4 spd car with some gear 3.91/3.73 typical gears.

Does it have the tq of a 340? no.
Does it rev like a 340? Yes.
Is it fun to drive like a 340? Yes.

2 out of 3, good enough for me.

That said, add heads....
Or a 4" crank.
Will a 390 stomp a 360, yes.
It's more often apples to oranges in the real world aka anything can be made to out perform.
So this becomes more of a.. what I'd do vs what they'd do, you'd do etc...