so I drilled and tapped the busted front 3/8" threads to 7/16. Didn't take much material out and I took the water pump off and had my shop vac pull the metal out down through the cylinder head bolt hole so no shavings went where they were supposed to go. Thread looks fine. Now I just need to pray the rear bolt hole holds up.



Still blows my mind that those fewer threads held up to 35 ft/lbs.


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