Don't forget the brakes. Once the axle is swapped, the front and rear bolt pattern will be different along with the brake size front to back. Disk brakes up front is easy enough to do, just more money and time. At least they do bolt on without any modifications. While you adding front brakes, might as well go with new kingpins and steering joints. Modern sealed tie-rods will also bolt in. Then start looking for a '41-'46 steering box for a slower ratio and modern roller balls inside for easier steering.
You could always just swap out the ring and pinion to the 3.55 sets being sold and then drive it as it is without the high rpm.
I would suggest getting it in good driving order and put some miles on it to get a feel for how it rides. These are not the best riding trucks due to the short wheelbase and heavy springs. Mine has leafs removed from each stack and teflon liners between each leaf which helped a bunch, but it's still a truck and still rides fairly rough. They are also very tight in the cab with two people, where you live you may not need A/C, but here in the Midwest, it's hot and a/c is almost a must. Thats next on my list of things to do, after 15 years of not driving in the summer heat, I am ready.
So to answer your question, YES it's a very slippery slope,
Joe
