[billheis]

I believe that 88 is talking about newer heads that are have bolt down rockers which you put shims under the fulcrum. If you have 74W heads you have studs which weren't adjustable from the factory. However Mr. Gasket, Crane or Comp sell posi-locks, which are just like what come with roller rockers. I believe the thread size is 5/16. What you want to do is get the cam on its base and start tightening down the nut while spinning the pushrod. When all the slack is out go another quarter turn then tighen the allen set screw. I'm also assuming you're still using the rail rockers. After you have everthing set, rotate the engine and make sure the rails on the rockers aren't pushing down on on the retainers. The cam you are using has quite a bit lift and the rail rockers really weren't designed for that much lift. If they contact the retainer it can actually push the retainer down and let the keepers come out and then, well disaster. Hope this helps.
Bill