OK, first of all you're .175" off the mark. But you're thinking BACKWARDS. "Shims" are gonna make your problem worse by raising the spring height, basically raising the bottom of the spring by whatever shim you throw under it.
If installed height is supposed to be 1.650 and you're at 1.825, you're already to tall. You need to take shims OUT. Look around REALLY carefully, sometimes those suckers are hard to see. They stick to the head, the spring, etc etc. Get yourself an icepick, start feeling around the spring perch, and you might be surprised at what you find.
