Darren, let me ask you this. Are you coming back after assembly and tapping the end of the valve stems with a small hammer to insure the locks are properly seated? Failure to do that could be why you're getting a short installed height measurement.
x2
It's the diameter of the hole in the retainer, thickness of the locks, and angle of locks that will leave things in the right spot. That's why I'm concerned the locks themselves might be thicker and therefore sitting higher in the factory retainer. Dykem would show that point of contact.
