I contacted Arizona Differential Specialists, the guys who replaced the hack job C body axles with correctly sized Yukon axles and sealed up the rear end.  I asked them how much they would charge to swap out my current 4.86 gears with 4.10 ones, and also asked them if they would be willing to pick my car up from my house.  They responded a very low price for the job including parts which made me very happy.  I asked them exactly who makes the gear they will put in – and the answer I got is US Gear / Strange.

I highly recommend those guys – they’ve gone far beyond my expectations.  I will be contacting them next week to let them know when they can pick up my car to do the job.