I have an 85 F-350 with 460 installed. It's the original motor. My question is, is there a heat cross-over under the carb. similar to that on a small block GM? I didn't notice an abvious runner as is present on the small block GM. I haven't been into this deep enough to know myself, but I am having cold runability issues.

 

There is a cross over on the intake. It comes from the #3 and #6 cylinders. Chances are that it is choked up with carbon hopefully.