I want to purchase a tap to chase the threads in the block before re-assembling the motor, but cannot seem to locate the appropriate size tap.

SF.c search is hokey, so it is of no use.

I figure it is 12x1.xx, I assume maybe 1.50, but cannot be certain.

 

ON the GS they seem to favor 1.5 pitch for most things. But to be sure ytou can do what I did.

Take one of the bolts to the dealer or any shop actually they have a little tool that looks almost like a feeler gage . They can lay the tool against the bolts and can tell what thread it is.

 

I took the ARP head stud to Lowes to do that exact same thing, and it didn't fit well in 12x1.50 or 12x1.25.

DOH!

 

Did you fit the "ARP" head stud to any standard SAE sizes? You may have received the wrong studs for this engine. To an untrained eye, they look almost the same, but the threaded aluminum hole knows!

 

The ARP box says they are correct, and they thread into the block just like any of the other ARP stud sets I have done on various motors.

I know they are correct, but the tool at Lowes could have been F'd up. I will pickup my own tester this weekend.

 

Agreed.... sorry, I missed on the Lowes tool!