when i drive down the road and come to a stop sometimes my oil pressure will go down to 0 and blue smoke will come out of my exausht. what is this from, blow head gasket, piston ring?

------------------
72' Chevelle SS (Clone)
TC Member#1417

Sounds like your oil is hitting the crank and throwing oil into one of your cylinders.
Do you have a pan with a baffle or trap door?