I was looking at the possibility of swapping spindles from a later truck (5/10 P-30) to the stock front end and it looks doable but I will need to see all the parts in hand.
I presume you are thinking one of the straight axle trucks. I suspect Grigg has already researched this option some and may have some good reasons why it doesn't work. But please keep us posted on what you learn because it would be great to find a solution for these trucks.
My "problem" with narrowing the axle is not the "doing of it" but the final product. I have my concerns about welding a large truck axle back together
While I can appreciate your concern and if I were the one doing the welding I'd be worried, I believe a good welder can make a joint that will be as strong or stronger than the surrounding material.
The choices manufacturers make are based on manufacturing scales that mean many of their decisions are backwards from the economies of making a single part.
As far as fitting the 6BT in an AD truck engine compartment, the space is there for the most part. Plenty of height, slightly narrow (but with a little metal shaping to make clearance where needed in the inner fenders it shouldn't be a problem) and length, the "hard" one, the 6BT (from web resources) is only 6"+/- longer then the stovebolt it replaces, I can push the center of the fire wall back to give clearance at the rear of the head and maybe hump up the tunnel for a bit more clearance.
I've studied a number of these swaps both online and in person. The 6BT is a long motor and does not really fit in the AD truck engine compartment without modification.
The best looking swap I've seen was done by a guy local to me. I have a bunch of pictures of the truck, though my focus was on the IFS conversion rather than the motor swap. I have long since rejected the 6BT as an option for my own project.
It will take some poking around to find it, but its the 1-ton GMC with the full body camper in these three sets of pictures.
The old guy standing next to it built it about ten years ago and says he has driven it tens of thousands of miles since. I believe him.
Aug 08 Feb 09 Aug 09 This swap looks good enough to have come out of a pro shop. None of the others I've seen are nearly that clean and well executed.
The dana 70s and 80s that come out of the P-30 trucks, how do they stack up to the stock rear for capacity? They seem to be somewhat lighter duty and the next step up in modern equipment seems to be 2 1/2 ton or bigger.
I believe you are correct. I'd suggest starting with a calculation of exactly how much capacity you need. You may find that these axles are not up to your task.
If we assume the 6500 weighs 6000 now its going to get heavier with the 6BT. Its rated for 16,000 now I believe. I don't know the ratings on the 70HD and 80 rears but suspect you're giving up some GVWR going with one of them. I can easily see building a truck to carry 10,000 or 12,000 using one of these rears, but keeping the 16,000 rating isn't likely.
I've not come up with my numbers just out of the air. My P30 motorhome has a GVWR of 12,600 pounds so I assume those drivetrain components are up to that much.
Thanx for the input and questioning, it makes me do more research and that can only help the project to go smoother and the end result be better.
Jaysin I'm currently on temporary disability and those days I can get my head into the game I enjoy nothing more than trying to figure this kind of stuff out. I'm happy to be part of the dialog and really appreciate having something interesting to think about!
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