wont spin

I still think that your carb is to big for that lower stall converter. The engine is trying to come on earlier when the velocities through the carb are lower and with a large carb like the one you're running the symptons will be more pronounced than with a higher stall converter. You may also want to look a better flowing intake manifold. Also, I can't picture the operating mechanism for the secondaries on a quadrajet but trying rigging them so they can't open at all and then see if the engine still boggs off the line. They could be opening to early and if it was a Holley or a Demon it's a simple spring replace.JMO

Terry