1936 1.5 ton transmission swap

[Charlie36]

I have a 36 1.5 ton truck with original 21 stud and I believe 4 speed I'll be starting work on soon and would like to make it a little better for longer trips/higher speeds. I've done some research and understand the T5 can be adapted to a flathead relatively easily but I'm not sure that would be a good choice for a bigger truck.

If the T5 isn't a good option for a 1.5 ton is there a better transmission out there that would work? I would like a 4 or 5 speed.

I've found some posts mentioning the NV3500/4500 and others saying they would not fit because of the shifter location.

Appreciate any insight anyone can give. This is my first post but I will attempt to attach a picture of the truck without messing it up.