Overheating Intake Manifold - Help !!

[68dontneedanewone]

Here's the deal......... 72 V8, either 350 or 400 small block ('new' truck, haven't checked casting numbers).

Son took a rock in the radiator and severely overheated it.
Got it home and had water droplets out of both (duals) tailpipes, but with 150lbs +/- compression in all cylinders, so figured it blew the intake manifold gasket.

Replaced the manifold gasket and sandblasted/painted the manifold while I had it off. Should have taped off all the openings, but didn't. Used 100lb air nozzle to blow out all passages afterward.

Now the truck is 1) hard to start when hot, 2) diesels after shutting off, 3) expels gas/air mixture or other smoke-like substance through carb/air filter housing, and 4) manifold has turned black over both sides of center water channels (between #2-4 and #3-5 intake channels).
Timing and dwell are spot on the specs.

Any ideas on what I've done, or what might be the problem/fix?

Thanks for any ideas,
Earle