Ouch.....
I think that was one of the things I mentioned earlier that could be a possible cause.
now the question is.....WHY?
did you have the heads milled or block decked or anything?
any other machine work done?
did you clay the pistons the see what your clearances were?
hopefully it was a fluke and a tiny pebble or something fell down the intake and got caught between the valve and piston.
have you accidentally dropped any nuts or bolts down the intake (maybe a jealous friend was over and while you were not paying attention dropped a few tiny rocks down the carb all the while mummbeling to himself ( MWHOOOHAHAHAHA this will put a wrench in the gears) LOL......ya never know lol.
also ,check to see if all the screws are in place on the butterflies on the bottom the the carb..... sometimes people rebuild a carb and ruin those screws and end up drilling and tapping the shaft and using a regular screw.....or sometimes you may find that one of those screws were not flattened on the shaft to stop them from backing out.
I bought a GMC jimmy a few years ago that had a knocking engine and was over heating and puffing white smoke ..... The guy I got it from had just had an intake gasket done on the jimmy....afterwords it developed all the problems I just mentioned.
I tore the engine down and it turned out to be that the mechanic he had install the intake gasket dropped one of the TINY screws that hold the distributor cap to the distributor base and it fell down the intake.
when he started the engine that tiny screw smacked the bottom of the head when the piston got to TDC and it ruined a rod bearing and it tipped the piston and cracked the cylinder wall and was allowing coolant to flow into the combustion chamber (causing the over heating and white smoke).
so make sure to inspect it well for any piston and cylinder damage aswell.
good luck!
