I usually just link to the Novak Transmission SM420 page
http://www.novak-adapt.com/knowledge/transmissions/manual/sm420but, here is ID info from Novak:
1947-1953:
No ribs on the case
Grooved worm on the input shaft instead of neoprene seal
Synchro rings all differ from each other. 1st-2nd synchro ring is bronze
Weep hole at 6 o'clock on the bearing retainer snout
Six digit casting number on the case, usually like "59xxxx" e.g., 5916651954-1963:
Same as previous but uses a neoprene input oil seal
No weep hole at 6 o'clock on the bearing retainer snout
1964-1967: Same as previous except
1st-2nd synchro ring is aluminum and 3rd-4th synchro rings are identical to each other
Seven digit casting number usually like "37xxxxx", "38xxxxx" or "39xxxxx"
1968-1981: Military Con-Diesel version. Features the strongest case and optimized internals. Usually equipped with unique top cover, but can be converted to standard top-shift control.
590474 = 59xxxx = 1947-1953
My guesses are that the "1s" in the following code contains the year in a date:
F 16 1 = May, 16th 1951
B 17 1 = February 17th 1951
Let's try one thing at a time:
What is your engine serial number?
What are the other casting codes shown on this page:
http://www.1954advance-design.com/Web%20images/casting-code-photos/low-press-codes-ser-nums.html What are you trying to ID?
- "rolling chassis" : cab? frame? drive-train parts?
- engine?
- transmission & rear end?
