Hmm, drill and fill the hole with a swab of JB weld? (it's hell tricky but it could be TIG'd up - die cast metal is not easy to work on especially if it's already dicey...) It sucks that you got a bad part but it happens. I was expecting lousy machining but a bad casting? Should've seen the factory head from my G63B, you've never seen such a poor quality production head from Mitsubishi... Yay -Garrett! That will make sure it can get out of it's own way. Whatever you do, don't take out your frustrations on the truck. It's a victim as well and you're along for the ride. The oil pressure issue is but a small hurdle and even though the oil leak was caused by a bad part, you found the source.