did the kit come with retainers too? If so, I would take it apart and check the retainers and keepers again. when you assemble heads, make sure the keepers and retainers and valve stems all match up (yes there are different keeper degrees of lock), and the important thing to remember is, when you assemble the springs, etc. Tap the top of the valve stem lightly with a hammer just enough to make the valve drop alittle just to make sure the assembly is locked in place, and if aint, you want to find out now, and also get some knee pads because finding those little keepers on your shop floor will be fun.
