Starting problem

Thought I would see if anyone might have an idea of what's going on with my 318. It will fire right up and run like a champ, I let it warm up to temp and shut it off.
If I try to start it right back up it starts fine. If I wait about 10 to 15 minuets it won't start. Acts like it is flooded out or vapor locked. I do have a spacer under the carb. It will actually kick back like the timing is off and spew fuel back out the carb.
We took the carb off and went through it because it has been 4 years since it was used and couldn't find anything wrong. I've tried 3 different pressure regulators on it also with the same results. I had them set at 2 to 3 lbs.

This set up worked fine when I had it in my old dart, only difference is I now have a mechanical advance dizzy in it. Timing is set at 18 and tops out at 32 at 2500rpm's.

Electric fuel pump, checked flow through filter and pressure regulator and all seems fine.

Carberator is a Edelbrock 600.

Still thinking maybe I need to go buy a Holley!