[kbs71]

I had this exact same thing happen to me a couple of years ago. I had just put a Holly on a Q-jet manifold. if you look at both sides of the carb at the manifold you'll see the manifold "disappears" under the carb. There is a gigantic hole there under the carb and will cause the thing to hesitate real bad at idle when cold. It will appear to get better as the engine heats up. You need to either get a manifoldadaptot to adapt the Q-jet manifld to a spread bore or you can look for a isolation plate for the spread bore. Put gaskets on both sides and it will stop the leak. this way isn't really the right way but it will work.