compression = horsepower query

Thanks guys, i can se where this thread will head!

I rebuilt my motor 2 years back with a modest power increase. Thing is, ever since i've been kicking myself for not going for KB107s and zero deck to get good compression. I really can't/won't spend a lot on heads as i had a fully rebuilt, slightly ported, valve jobbed smog heads put together for the motor.
So....if i am unwilling to splash $s on Eddy heads etc, I guess i may as well stick with what I have.
Or, to put it another way, probably not worth spending cash on block work, new pistons etc if I dont want to alter the heads?