Re: Do I need 7/16 or 3/8 studs; 327 ; r. rockers
Standard SBC rocker studs are 3/8". As mentioned above, a 3/8" rocker for you will be fine. My old 383 stroker used 7/16" stud rockers. To do this with a stock head that has pressed in rocker studs isn't recommended. If you have spring pressures high enough that you need a 7/16" stud, chances are you'll pull it out of the head.
If your heads have been machined for screw in studs, you just need a conversion stud to use 7/16" rockers. The thread hole in the head is still 3/8" so the head doesn't need to be modified. The top part of the conversion stud is 7/16". If your heads still have pressed in studs, they can be removed and the stud boss can be machined down and tapped for screw in studs.
Gen V BBC engines are the same way. From the factory they use a 3/8" stud, non adjustable, valve train. All other BBC engines use 7/16" stud rockers. To convert to 7/16" stud rockers so you can use normal aftermarket parts and convert to an adjustable valve train, you simply buy the conversion studs. Unscrew the factory studs, screw in the conversion stud and install any aftermarket BBC rocker. Normal BBC rocker studs have 7/16" top and bottom but they also see much higher spring pressures than most SBC engines.
If your SBC engine gets over 200 pounds seat pressure on the spring which means about 600 pounds open pressure, you may consider getting the stud holes in the heads retapped for 7/16" and use BBC rocker studs.
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87 IROC ET Bracket race car 540 alcohol big block
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Last edited by Stephen 87 IROC; 02-03-2006 at 11:08 PM.