Help with 340 compression + cam change

OK, I wondered about that, having realized my piston choice from way back was probably not a very good one. Didn't know that much and was following advice from "someone".

(I'll start by getting a new gauge and see what happens.)

If indeed the compression really is that low, I don't think I'm ready to completely tear down a nice running motor, but a different cam might make this work better?

I have long recognized I likely have a mis-match of low compression and high flowing heads.
(This was very high compression motor when I got it, but couldn't keep those "mountain" pistons for street.)