Screw in studs for Rocker
 

I have a Pontiac 400 6.6 L (dated 77, block # 500577,y4 samped on front) in a 1980 firebird. I am trying to figure out what size screw in studs and nuts for the rockers I need. Did most of the engines from the late 70's use the same size? I am pretty sure the rockers are stock. Thanks.

There is a ton of info on this site about this. A search should find everything you need. Might take awhile to read it but well worth it.

I decided to go with the Comp Cams Magnum Roller Rocker Arms since they are only about $30 more than buying the studs and nuts seperatly. This package comes with the 7/16" rocker stud, and nuts, and says it fits pontiac v8.

Do the heads have screw-in studs now? Some had press-in studs and would require some machining to convert to screw-in.

Just got verification that the heads have screw in studs. Why was the guy who sold me the car suggest I upgrade to screw in studs for the rockers then? He said the studs back off over time from too much power. Do the heads and rockers use the same studs? Thanks, again for the quick responses.

If it has the factory screw in studs (non-adjustable) then converting to an adjustable valvetrain is a good upgrade. Non-adjustable studs use a shoulder to torque the rocker nut onto and they can back off in time. Adjustable studs will use different rockers and poly-locks to securely lock in the adustment. Adjustable studs are needed for any cam larger than stock.

I've used big block chevy studs for 20 years- no problems.