Thanks guys, I just ended up starting to drill it through. The size between two of my bits is two big so I can't drill it out. I'm going to Home Depot or something to get the bit tomorrow I hope so that I can finish drilling it out. I just hope that tapping a cast iron hole won't be too hard.


69 Buick Special Deluxe. Intercooled Turbo Chevy 250 @ 15psi on a stock long block. It's kinda fast.