318 Non-Magnum [Valvetrain question]
I would bolt the rocker gear on, make sure all the pushrods are seated right, torque it all down put it together and bust it off. When I did the cylinder head job on my Ranger, it did about the same thing when I put it back together. Ran like hell for a few minutes and slowly cleared up. When pressure is remover from the lifters, they are allowed to extend all the way. I bet they will be fine once you let it run for a bit. Make sure you have the rocker shafts on correctly. There is only one way.