HELP: problems with heads!

[HotRoddin]

Absolutely ! Thats coil bind ... your cam is trying to compress the springs more than they can compress, (they compress until the coils touch and can go no further), at that point something has to give ... that it was the lock or retainer isn't surprising. If its coil bind and thats what it sounds like, then you have to get springs, retainers, locks etc that are compatible with the lift of your cam !! Not only had you better check everything up top in the valve train, you better check your cam as well, because coil bind can easily gall or round off a cam lobe. Also make sure it was valve spring coil bind and not valve to piston clearance problems, even though your symptoms are more consistant with coil bind.
Who picked out the spring, retainer, lock, valve, cam combo?? If it was you, you learned a valuable lesson ... if it was the shop, they should have known better and should at least share some of the expense with you.