I had my 302 rebuilt and I put a new holley 0-7448 on it.It runs great and idols great.the problem Im having is when I put it in drive it chocks down a bit and wants to die.If I set the idol where it doesnt do that its idoled to high in park.

 

Try tuning in the idle mixture with a vacuum gauge.

 

not sure if has anything to do with that but try checking your timing.