I have just pulled my valve covers because I was told that my engine has 10mm rocker arm studs. I was pretty darn positive that was not correct. I ordered roller tipped rockers from crane with 10mm polylocks a few years ago and I had to reuse my stock nuts b/c the 10mm did not fit. So when this guy told me my engine has 10mm I thought I was an idiot and had maybe not received the rocker kit for 10mm years ago. Well, I am not sure how exactly to check the stud size but I can slide a 3/8 socket on to the threads and it is not tight, it slides right past the threads. SO that tell me the studs are smaller than 3/8 right? am I an idiot? Obviously 10mm is slightly larger than 3/8 so they are definitely not 10mm. I want to order some full roller rockers but now I have no clue what size studs I have. Anybody? Any input is appreciated.

 

I think the holes in the heads are 10x1.50. The exposed threads are 9mm.

 

You need to order up this crane kit 99148-12, this is a stud kit. It has 10mm bottom threads & 3/8 threads for the rocker arm nuts.