Sounds like a reasonable plan.
I doubt you feel a loss of "power" with the faster 4.10 gears. Actually I expect you will appreciate the improvement in how it drives on the highway so much you then wish you had the 3.73 gears you wanted to start with.

When you get a chance please start a new thread so we can follow along with your progress.
If you learn things that need incorporating in this thread then we'll add them here later.
I've noticed technical "how to" threads become less and less useful the longer they get.

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-