Originally posted by Thunderbucket
The Backyard method was to have a set of old valve covers with the top's cut out of them,,put them on,,,and adjust when the engine was running untill the engine started to Lugg and then back off a quarter of a turn, (i think,,i'm getting close to you in age).
Originally posted by baggettjd
I will try that method, Thanks a lot. I just don't understand why I keep reading that the 68 429 thunderjet engine has non-adjustable valves and when I bottomed out the self-locking nut, boy my pushrods bent like crazy.
Do Not try The Above Method. This ain't no chebby nor are the valves adjusted in the manner that the chebby is.

Your 429 Thunderjet came from the factory with non-adjustable positive stop rocker arms and valve train. You just screw it together and you're done...sort of. Assemble the valve train and when the rocker nut botttoms/hits the shoulder, you just torque to 18-20 foot pounds. However, the rocker arm mechanism that is being installed must have it's cam lobe at the base circle. You cannot just throw the valve train on and then randomly start tightnening bolts, or indeed, you can bend pushrods. IF the cam is not at it's base curcle, final tension is forcing the intake valve to open and the pushrod must endure the preload.

Also, it may be necessary for your hydraulic lifters to bleed off, so if you are at the base circle of the cam, AND have the stock pushrods (8.673")/valve train, AND the bolt still won't bottom, then just leave it where it is and walk away for fifteen minutes and check afterwards to see if the lifter has bled down...then you may continue tightening.

(Incidentally, I am assuming this is a stock engine with OEM parts. Otherwise, if you are building a new performance engine, you may need a different length pushrod. If not, then disregard this statement.)

Paul