Get a piece of plexiglass, drill a couple holes in it, get some grease and a 100ML syringe (1ML is the same as 1CC) ,
measure your volume and calculate your compression ratio.

Comp 268, eagle heads with .075 gaskets, custom pushrods and long tubes is a known pretty happy combo.

https://www.youtube.com/watch?v=BNXVX8tolAY

If you want "the sound" but need it to be tractable, that's the easy route (or something really close).

If you DON'T want "the sound" and need it to behave really close to stock, then get a Comp 260.