Hi Crewman,
I'm new here as well so I'll add my 2 cents. I thought most Ute's were on a car chassis, but this is a very cool one obviously built on the pickup. Since the truck has been sitting a while, I'm thinking a donar vehicle is in order. I was shopping for a power train for a speedster project and I found a flathead six and four speed out of a three quarter ton that a guy is converting to a pickup with V-8 power. There are 2 different lengths to these engines ( either a 23 or 25 inch head) depending on the size and in my case in Canada, where they were built. They can both be made to fit in your truck, but it would be less hassle to keep the same length. If you wanted to step up to a 4 speed with the floor shift, they are out there, but don't expect to speed shift with them. Just thinking if you had to buy a vehicle to get running, that may be the easiest answer to your missing axle dilemma as well.