I have a 70 351W do the rocker arm studs unscrew outa the heads thanks

 

No Sir, they are pressed in
Clint

 

IF they are pessed in why is one larger from the rest? this is a rebuild, the rocker arm middle will not go over the stud all the way and I checked it with the others it works on every one ?

 

Someone put the wrong rocker arm in as a replacement, probably a 7/16 stud, and small blocks use 3/8(generally).

 

Brandon and Clint are both correct here.

Most likely scenario is where one of the factory pressed-in 3/8" studs had broken, and a machinist had drilled and tapped it for a single 7/16" stud, which is totally assinine since nobody sells rocker arms one at a time.

Some aftermarket heads use 7/16" studs, like World's Windsor Jr's, but 3/8" is pretty standard. It's not as important which one you have as it is to have all 16 of the same stud. You could possibly heli-coil that threaded hole so you could put a 3/8" stud back in. TK

 

THANKS FOR THE INFO GUYS so if the stud is pressed in over sized if you will, couldnt I change the small half moon I duno what its called,in the rocker to the bigger size to fit over the rocker stud? WALTER JOHN