I'll be doing a head/cam swap on my 99 vette and I was wondering if it's ok to drill 1/2' holes on the lifter cup. According to Will Handzel, he said it was to help drain out the oil that can and does puddle on top of the lifters. These holes allow the oil to drill back. Should I leave them alone or drill 1/2' hole?

 

There would be no negative effect and it would help oil drain back. You should highly consider purchasing a new set of lifter guides while you are in there. They do wear over time and tend to get a bit brittle, and there is a good chance they may crack if you try to drill the old ones. Purchasing new pieces is cheap insurance against a lifter spinning on you even if you decide not to drill them.

 

this isn't 1999 or anything.

search and your find 300 post with this topic

 

1999?

 

The cups keep oil pooled above the lifter. When they are full, they overflow. Drilling holes keeps them from filling completely but doesnt make the oil drain back any faster, just slightly earlier. You could counteract this by running 1/2 quart more oil. And no it wont hit the crank bc it will be stuck in the full cups, as opposed to 8 drilled cups that are half full.