Around here I wouldn't pay any more than $100 for a good usable as is SM420. Likely you can find good ones for well less than that, they are plentiful, strong, and less and less desirable now that we tend to drive fast and like/need OD transmissions.

Rear axle is worth about scrap value, and you should find some free ones if you ask around.
If you find one that someone has already and recently rebuilt/restored it should be worth slightly more than the value of the new parts.

Grigg


•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
---All pictures---
"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-