Need help 351C at Ranchero is going out.

Moin, I need help or tips. Drive 73er Ranchero with a 351er Cleveland engine. Sharp camshaft from Comp Cams, Edelbrock Performer suction bridge and Edelbrock 1603 carburetor with 600cfm. Alu cooler two E fans. 140ampere alternator us large Bosch battery. That before it brings someone to an idea. My problem: When packing etc. the car went off from time to time. So carburetor set. Speak mixture and speed. Idle speed in warm condition, at fully open The problem was gone. Now it came again and again and got worse. Say I drive everything is good. I turn at a traffic light on P or N and then put in a gear again the engine goes off. Get the car until I put in a gear again. Now it was so bad that it went off when turning off. So carburetor re-set so that a gear inside is fully on the brake and the climate is on. Carburetor is all right. Drive around everything in order. Will just so I don’t know what it can be. Vacuum hoses look good, as it often felt when braking at low speed. Carburettor was already lean, medium and fat set. Vacuum in P ca -0.35 and with inserted gear -0.26. What can it be? Mixture problems, speed, ignition, vacuum, false air? It’s not logically understandable when it occurs. Once I can park and crank back and forth as I want and once it goes the turn off. Even when only p was inserted and the climate etc was off. Mixture and speed was already set in all areas. Again and again sporadically this error. I am grateful for every advice.