My car shuts off when i hit the gas to drive.But the car as long as the car is in park it wont die.Whats wrong

The 84 cutlass is OBD- 1 and you have changed engines and the tranny.The computor can not control this set up and it is illegal if you are in California.It sounds like the throttle stepper set up is not in opperation to raise RPMs when put in drive and is probably why it dies when put in gear.If the Edlebrock is larger than a 650CFM the engine will flood at low RPMs and die.Wish you the best.

You either have a vacuum prob or a fuel prob.Id be goin for fuel.Check your fuel filter isnt blocked,and where the fuel line goes into the carb giv it a tap with a screw driver or small hammer as the internal filter could be blocked.Also give it a tune up buy adjusting the fuel air mixture screw.could also be a pump problem

This needs just a little bit more explaining. Does your car still run when you shift it out of park and into drive then die once you hit the gas? Or is it as soon as you shift it out of park it is killed?

I would check vaccuum lines, throttle linkage, choke, transmission fluid level. If you have to much tranny fluid you create to much pressure and it kills your car when you shift into drive and try to go. It just stalls it out.

that sounds like a disconected vacuum hose on the transmission, or something in the transmission isnt functioning properly

it could be fuel delivery problem or oxygen sensor and maybe catylac converter