Tune up questions

Here are the specs:
5.9 magnum. cam: oregon regrind 214/221*, 480/482", 110LSA. hughes spring kit. airgap intake. holley 600VS.

Currently 12 base timing and 34 total. Mopar electronic ignition, old orange box.

Car runs alright when cold, but when hot it wants to stall in drive. It also does not want to go past 4000rpm, at which point it loses power and backfires through the exhaust.

Ideas?