Okay, I just put on a new RPM manifold, Edelbrock #1407 (600 cfm electric choke), and a MSD ready to run distributer...timing is fine and idle speed seems just right..what I am experiencing sounds like a backfire for just a short period before the engine warms up, sounds like carb backfire, or spark plug kind of snap sound...happens about once or twice when accelerating, and goes away after fully warmed up.....I am thinking too lean..or bad spark plug...anyone have any 2 cents on it?

 

You could be off a tooth. Same thing happened to me, but it was so long ago I forget exactly what it was.