Originally posted by CATCRACKER
when drilling manifold this is what i did. i began to drill for a while with out grease and once i started getting close to breaking through which is about 1/4" i started the motor with duct tape over the tail pipe and greased the drill bit put on your safety glasses and the little chunks of metal were flying back at me. . a good thing, did the same when i was tapping the hole. the diprocol used a 21 32nd drill bit with the 1/8 tap. i drilled and tapped a piece of sprinkler pipe before attemting to drill the truck and guess what i had a drill bit that was to big in the second attempt into the test pipe it was perfect. left about 3 threads out on the tap and this whould have centerd the prob in the perfect spot. i was nervous but it worked perfectly.
run a test drill and tap first this advice will save one of you who reads this.