85 T/A, mods are in sig. the car starts fine (gotta love msd), but it runs horrible. it won't idle unless you hold it above 1500 rpms for 30-45 seconds, then it barely idles at 500 rpms, and it feels like it's trying to shake itself to death. it sounds like its got a HUGE cam because it lopes so much. also, there is a billowing cloud of white smoke with maybe a hint of grey coming out of the exhaust that smells strongly of gas. HELP ME PLEASE

 

OH boyyyyyy, sounds like a blown head gasket to me.

 

it happened when i bolted on my holley after rebuilding it. could i have messed something up in the carb that would make it run like that?

 

Hmm.. Yeah,.. sorry man. Check your oil and coolant often. Do you have another carb you can try?

 

Sounds like you have a pipeline carrying fuel directly from the fuel pump to the intake manifold.
There's your clue. You got something in there wrong. I'd bet you used the wrong power valve gasket: there are 2 styles of gasket, and 2 styles of PV, and they don't mix.