carb, timing, or fuel delivery 350 chevy???

If there is anyone that can help. I have a '46 ford sedan, late model camaro front clip with 350 engine. it has edelbrock street performer intake and edelbrock spread bore carb, all else is stock on engine. Have done a complete tuneup on engine including replacing hei distributor, the engine runs fine at idle when i start it and runs perfect untl it shifts into drive and then it falls on its face as if it loses spark to some of the cylinders, or getting to much fuel. fuel pump is manual on block. It never recovers until i shut off engine and it cools slightly and restart engine with same results almost everytime, i am out of ideas and need help

I'd look for a vacuum leak.

When did this problem start? Is this a first start-up on a fresh engine? What is the timing set at? Do you have another carb you can put on just to try some trouble shooting and elimination of problems? Did this start after you replaced the HEI or before?

sorry about not enough info, i have tried a quadrajet, and a holly, with same results, and the problem was there before i replaced the HEI

Does the misfiring also happen when the car is in neutral and you just rev the motor? Or is it limited to when it is pulling the car? Are the spark plugs all the right color - a light beige? Could you have any lifters that are not bleeding down fast enough to let the valves fully close above idle rpm? IF this were a conventional ignition, and the symptoms were really inexplicable, I would suspect a bad condenser. I dont know how the HEI systems work though.
With a little work you can have a two-piece spark plug wire - having a gap in the middle of it where you can watch the 'spark'. Then see if the spark begins to die at the same time the engine begins to misfire. This would tell you if it were a failing ignition, or other cause (fuel or compression).
If the spark plugs arent dark or wet, the fact that you have to shut it down and give it a few minutes before it will start and run okay would lead me to think it was ignition related.

Is the replacement distributor new? How is it being powered? Later model column and fuse box perhaps?

Ignition modules is at the top of the "let it cool off for a minute" list. That or its losing spark or flooding out, or both losing spark and then flooding out.

If your sure the distributor is good parts inside and out run a jumper wire from the battery straight to the distributors power input and see if it still does it. If that cures the problem the solution should be obvious.

Whats the 350 out of?