To follow up on the earlier discussion of adapting spring perches to fit a little larger diameter axle tube.
Here is the before and after of what I was working with for a 14 bolt axle https://goo.gl/photos/6mnKfuwDs65uqf568
Purchased aftermarket spring perches for an IH Scout because that is what is available for 2" wide springs, unfortunately for 2.75" axle tube. The 14 bolt has 3.375" axle tubes (I had dimensions wrong earlier).

Anyhow that picture illustrates the small amounts of material to remove to adapt smaller diameter perches to a larger diameter axle tube.
I changed it 5/8" and you can imagine 1/8" change would be very slight; short work with a decent half round file.

Of the several aftermarket spring perch choices these are what I choose and they are very sturdy and nicely made, right on dimensions and square, also longer than many perches available including ones sold for trailer axles. Another advantage is they include alternate center bolt holes in top which for an AD truck would allow you to center the rear wheels in the fenders if you so choose.
http://www.ruffstuffspecialties.com/catalog/springperchantiwrap.html

Grigg


•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-