1972 Demon 340 engine mods

I'm going to be gone for a week but post up what octane gas you are going to use and how they measure octane in Warsaw
perhaps AJ then will calculate your Dynamic compression guesstemeate based on your cranking compression and can advise on a cam that will optimize for your build
that cam you mentioned is bigger than the stock 340 cam which is too big for a low compression motor (till you get it really reved up)
how are you going to use it?
did you say what exhaust?
sorry about the rear end- another thread has the 3.41 8 1/4
spend some time tuning the advance curve and let us know what you come up with
your current build should run better than you say it does
cam could be retarded