*GASP* Pennzoil. Try switching oils, number one. Pennzoil is sh*t. It sounds like a lifter to me because it isn't getting primed and is ticking...open up the top end, change the lifters, gaskets, etc. and pre-lube them with GM Lifter/Bearing Lube...kinda looks like red Loctite.

That should get it taken care of.