Bottom end info?

Thanks for the info.....that's the kind of stuff I'm looking for. Actually the lift/duration on the Crane is not far-off from what I was running. As for fuel, I was planning on mixing unleaded premium with 100LL Avgas at about a 15:1 ratio (FYI, 100LL has about 4X the amount of TEL as 80/87 Avgas....it was deemed Low Lead after WWII in comparison to the 115/130 Avgas used in the fighter aircraft which had a LOT more TEL in it to avoid detonation at altitude in supercharged engines). Let's just say I have my sources. Anyway, I appreciate your advice on the CR & the heads. I may have the J heads CCd a bit more tp bring down the true CR to 11:1 although I never had a detonation problem before (to my knowledge). I would hate to CC a set of X heads to match the pistons and ruin them for a stock 340 setup, if you know what I mean. It might be cheaper to have 2.02's installed in the J heads, if you think it would make much of a difference.
As for ignition, I was running the stock Mopar electronic ignition with a Mr. Gasket quick-advance kit & no vacuum advance.....it ran like a scalded dog! My machinist feels that this system is outdated and I should go with an MSD with programmable advance curve and rev limiter. I guess I have a lot of research yet to do on this.....the last time this motor ran was when Reagan was in office! (d'oh!)