To find out if you have a 1941 235 engine, use the casting number, NOT the serial number. Confirm on web page http://home.znet.com/c1937/Cast.htm. The other way to identify a 235 is pull out the dip stick. If the hole is threaded, it's a 235. If it's smooth, it's a 216.
Chevy used a non-syncromesh 4-speed with 6 bolt power take off, from second series 1931 - 1940 and an interchangeable 4-speed from 1941 - 1947. The difference being the earlier trans had one more tooth on low gear giving it 7.22 : 1 in low vs 7.06 in low. http://home.znet.com/c1937/RPM.htm.

@lou-macmillan I appreciate the information, those links seem to be dead for me though.

I'd like to hear thoughts on getting cheap tires for easy loading of the truck.

Can I just get some 5.50 16 tire tubes and stuff them in those tires. Looking to make trailer loading easier. 

Learned the gearbox was free when they moved it, Dad was able to get it into N so that was good to hear. 

To access the web pages use home.znet.com/c1937/Cast.htm with no period at the end for casting numbers. For transmission and rear end ratios use home.znet.com/c1937/RPM.htm with no period. Your stock rear end ratio is 4.56 : 1 with 9/41 ring and pinion. A half ton rear end with 4.11 gears will bolt in.
Your stock tires are 7.50 X 15". Half ton are 6.00 X 16. One Ton are 7.50 X 17" with 5.14 rear gears.
Glad to hear your trans is working.

home.znet.com/c1937/Cast.htm

home.znet.com/c1937/RPM.htm