Ive heard to make a removable baffle inside a dohc b-series valve cover you can
drill out the rivets and tap them. anyone had any experience/pix? drilling isnt hard im wondering more of what side drill bit, what size tap, and what length of screws/allens were used....thx for any input!!

 

why are you needing to do this? are you fitting in AN summit weld in fittings for a vented valve cover?

 

yeah i want to tap the fittings in and get all the metal out of there and it was powdercoated so theres gunk baked inside.