Helicoil size

Hi:

Do you guys know which helicoil size should I get to repair the threads of the rocker's cover?

Thanks in advance!

sparkplug said:

rocker's cover?

Click to expand...

Do you mean the exhaust rocker cover stud holes that take the 1/4" x 1" 20-26 tpi 067582 (NMT2252) studs?

If so, then the thread form should be 1/4" - 20 tpi Whitworth, I don't think they ever changed the cover stud threads to 1/4" - 20 tpi (60 deg.) UNC, as the same studs were used from 1956-on, apparently?

The thread in the cylinder head for the single 067693 inlet rocker cover stud is 5/16" - 22 tpi BSF.

Thanks a lot!!