[pydnar]

I had a 72 El Camino with that engine and a Holly 4 barrel quadra jet carburetor. We ran the timing at 2 degrees above TDC because in two different places it gave two different settings. Two degrees above was the correct timing for that catruck, at zero she wanted to die. And yes make sure you check the butterfly floats to make sure they are working properly, for all possibilities it could be bent slightly and you not realize it making it not be at it potential. I've had that happen as well.