Z head and O head on 1973 340

At what cost? How thick is your wallet? What concessions are you willing to live with?

Imnot a numbers guy. What I do know is subject to correction. AFAIK, the ‘73 came with 1.88/1.60 J heads and the compression dropped significantly!

Building this engine up like a speed shop got it and then “Enhanced” the package is a wide and varied list of parts to what company did what. Shy of piston replacement, getting the compression up on a low compression engine would require new pistons. Milling the head and then intake to fit is a good cheap route seldom done by way of compare to new pistons. Then the head itself has to be addressed. How far do you want to take it?

The thing is, you could build and build and build this engine by just throwing money at it while it snowballs into a F.A.S.T. engine.