340 camshaft question, yea another one.

You have 16 initial and 14 in the can hooked to manifold vavuum?

If that's the case the car is likely getting 14* of timing pulled out when it goes in gear. Just a guess the engine would want at least 20 initial BEFORE any vacuum can timing was in play.

No way should that engine idle at 850 and die when put in gear if it has 16+ initial timing. Nor should the carb need bypass holes drilled in the plates. IMO, the camshaft is NOT your problem.