I did the same thing as Squire. I used the stock bevels to convert my 5" gauges also. That'll work. Looks good that way too.

Unfortunately, I need to pull my brand new Autometer speedometer out again after all that trouble because it doesn't work. It needs to go back to the factory to repair.
My guess is Autometer is beginning to use Chinese electronic components or maybe getting their entire gauges made there.