looking at puttin the 306 in the motor what all the top end stuff do i have to change to do it.

 

Mainly springs, retainers, locks and a good set of pushrods. Other things are optional like upgrading the rocker studs, rocker arms and using guideplated depending on what type of rocker you would opt to use. New valve seals would be a good idea when you're in there and honestly, there's no way I'd rip it that far apart and not put a new timing set in it. I'm sure more of these guys will chime in with opinions but I hit the basics