Pontiac Press in Stud Conversion, 7/16" Rocker Arm Stud with 1/2" Bottom 389/421

Set of (16) RAS3 (studs only)

Requires 7/16 lock nuts or poly locks

Coarse thread length .75"

Fine thread depth 1.00"

Overall length 2.25"

US MADE SCREW IN Studs - set of 16

These replace Press In Studs on 389 and 421 heads. Very Popular for 64-66 GTO's and Big car 421's High quality studs are 1/2" course thread at base and stronger then factory 7/16 threads at top. Heads will need machine shop to pull studs and tap to 1/2" thread It is not recommended to hand tap your heads !!! Your studs may not be perfectly straight when installed. Normally you have to tap and heli coil for a 7/16 base thread, machine stud boss and then cut down the base of the screw in stud. to allow rocker arms to fit under stock valve covers. This kit is a time and money saver!!! Studs do not have oil thru holes on certain pre 64 heads, simply use rocker arms with oil hole On oil thru stud applications, I also plug the block with 2- 1/8 npt pipe plugs at deck to keep oil away from heads. This set up will allow factory valve covers to fit! These studs are for all stamped steel rocker arms (factory with oil thru hole) and also roller tip rocker arms. Some aluminum and stainless steel rocker arms will work as well.

Since all the heads are different, there is no generic torque spec. 

Some of the early (pre 1964) heads were oil fed through the stud and once removed do not have a lot of material to torque the studs. Those heads can crack easily and they also need rocker arms with squirt holes.