Well I'll keep the thread going for you a little longer on your first post. I really know little about the 428 CJ except that that is a desireable engine that ought to be fixed. If the valves floated at 4000 rpm they may have just had old reused springs, very tired springs. The first question is whether the bent pushrod also bent a valve. The first thing I would do is have a compression check to find out if the valves are sealing and check for a bent valve where the pushrod was bent. If the valves are OK then the next thing to do is to replace the springs with either new stock springs or performance springs. There should be a Ford Motorsports catalog at a number of sites including Pep Boys shops which offer racing parts for the Ford big block. As far as I know you will have to remove the heads to change the springs and that would be a good time to have the valves refaced as well as replace the springs. Lifters can't be that expensive so it would be a good idea to replace the lifters too. All of that assumes the bottom end of the engine is in good shape wrt bearings and rings. Well there other people on this Forum who have expert knowledge of the big block Fords so I will kick this up to the top of the thread list and hopefully one of them will give a better answer. Welcome to the Forum, there are some real experts here, but they have to sleep sometime(??????).

Don Shillady
Retired Scientist/teen rodder