I just put a holley 750 double pumper on it and it wont idle unless its over 1200 or 1300. I have had a lot of trouble with this rebuilt motor. Its got a stock cam in it but i cant get it to idle or go into gear without cutting off. What is my problem? I tried messing with the timing but i dont think thats the problem. The engine feels like it skips but all the Plugs fire well. Help me get this thing on the road please.

First guess would be a vacuum leak. Make sure ALL vacuum ports are either in use or plugged. Might try plugging all of them up as a test, even the PCV valve port. And, make sure you have the correct gasket for the carb base to manifold.

Sounds like it's lean.

Are floats set,air mixture,timing?

What dist. are you useing?

I think the 750 is border line for 454's ,might need to jet up some.Anyway you might want to do a search here or some of the other forums.