Technical Pop Through Carb and Running Bad, What Happened?!?

I have an idea what happened but want some input. I just swapped a 327 into my coupe with a Weiand 4 deuce setup running Holley 94's. Fired up the engine on TDC and it sounded great. At this point I should have left it alone but had a buddy come over to put a timing light on it and in doing so we advanced the distributor so much it made a loud pop (followed by a whistle) through one of the carbs, at which point I quickly spun the dizzy back to TDC (roughly) but now the engine instantly sounded completely different, like it was misfiring or not running on all 8. It sounds awful and now stalls as soon as you put it in gear. Think I just blew out a power valve or two?? Really hoping it's nothing worse... Any thoughts?
-Dean

 

Power valve's are a good place to start