Oil Port#1 for 4G63T

[Goat Blower]

This is the first I've heard of oil pressure to the head being a problem. With ten parts cars popping up every day, I can't see why anyone would mill their head more than once where this would be a problem. In fact, the high rpm drag guys are getting too much oil pressure to the HLA's making them pump up and cause problems, hence modified restrictors being sold like the one Kiggly makes. That's probably why you haven't seen this mod before. I always chamfer both oil and water ports slightly after milling, but only for cleanup purposes. Maybe this is a good thing, I'm not sure.