Mikey,
What are your plans for your truck?
Do you plan to put disc brakes on it? If you are, then it would be a good idea to put roller bearings as well.
Do you plan to keep the 6 lug pattern?
There is a 5 lug disc brake kit available for the 29 to 40 1/2 ton trucks. It basically uses Camaro rotors, and roller bearings on your stock spindles. The Kit uses 11 inch rotors.
There is another kit that is available for 41-59 trucks that uses the stock 6 lug configuration. You will likely have to use spacers with the stock wheels to prevent the caliper from rubbing. The 6 lug kit uses 12 inch rotors that are 1.25 inches thick. This kit will not fit on a 1940 axle, but a 1941- 1954 axle will fit on your 1940 with no other modifications.
The later axles use a larger king pin which actually makes them stronger.
This basically gives you 4 options
1. Keep your truck stock
2. Upgrade to 5 lug disc brakes
3. upgrade to a 52-54 axle and get bendix brakes, which is much more efficient than the huck brakes on your 1940
4. swap out front axles for a 41-54 and get the 6 lug brake kit and roller bearings. (or 5 lug kit)
I forgot there is 1 more way to go on this... you could get a dropped front axle and put disc brakes on it.
On my 1940 GMC I opted to go with the 6 lug kit and a later axle. I will likely order a 3 inch dropped axle in the next couple of weeks.
John
