If you have Vic jr heads then you have stud mount rockers not pedestal. You have to adjust the valve lash and the tighten them down by hand. If you have a hyd. roller cam then follow these steps.
loosen the rocker nut and loosen the allen head screw inside the nut a few turns. Tjighten the rocker nut by hand while spinning the pushrod between your fingers. Tighten slowly until the pushrod just quits spinning. At this time tighten the allen screw by hand and then take a wrench and tighten the rocker nut. It should turn about a 1/4 turn. That valve is adjusted.
Now, each valve has to be adjusted while the lifter is on the fully closed side of the cam lobe. Follow these instructions and you will be fine.
Turning the engine over by hand, watch the rockers as they move: Adjust the intake valve as soon as the exhaust valve on the same cylinder starts to open. Adjust the exhaust valve when the intake valve has opened all the way and is half shut again.
Now, if the engine is still doing this after the valves are adjusted then take a look at you timing. If you are running too much timig at start up or a locked out distributior it will have a hard tim cranking. Then I would recommend you get a start retard box or put your ignition (I'm assuming you have an MSD or mallory ignition) on a toggle switch.
