Multiple piece wheels can't be welded together because you then couldn't then install the tire.
If you want one piece wheels find some 22.5" ones.
If you want original wheels then keep what you have, so long as they aren't the Firestone RH5, and don't modify or otherwise play around with them and your welder...
Again refer to the tech tip.
As you contemplate your gear and speed options run the numbers through a gear calculator.
http://www.onlineconversion.com/bigger_tires.htmKeep in mind that a B series Cummins is happy cruising along at 1,800-2,000 rpm in a truck this size. The tire outside diameter for 8.25-20 or 9R22.5 should be about 38". And an NV4500 5 speed has 0.73 OD ratio, you're unlikely to find a faster OD unless you choose a 6 speed Allison automatic (electronic and more expensive option).
The original rear axle should hold up just fine to a Cummins, the big problem is lack of suitable gear choices. For that reason you should look at newer axles that within reason allow the speeds you desire. Or settle for a slow truck, which was just fine when it was new and can still be useful.
I would not graft a dodge frame to the original, while it could be done I feel that if you're going to go that far may as well borrow the whole donor frame. But I'm not a fan of that all, I much prefer to make the mechanical upgrades to the original frame, it makes for a much simpler and better looking solution, perhaps no more or less work in the end.
Have you measured a Cummins and the old truck to see if it'll fit nicely or require firewall modifications? This whole project could get complicated fast.
I know my own diesel bigbolt project is pretty straight forward but all the details and making everything fit and workout is a whole lot of work, thinking, problem solving, money and a tremendous amounts of time.
So far the big bolt wheel tech tip has the answers to your wheel questions, please check it again and let us know if you then have any more questions.
Grigg
