Even if the 55-62 third member doesn’t directly swap into your housing….it would be easy peasy to adapt a complete rear into your truck. They are still very common and usually CHEAP…. if not almost free. So many people take them out for 5 lug swaps and/or hotrod projects. You will get Bendix brakes out of the deal, if you haven’t already upgraded those.
As for gear ratios, I sourced a replacement for my worn-out 55-62 rear and completed the swap recently. I “accidentally” ended up with a 3.38 gear set. Whether they are modern gears or old gears, I do not know.
I was concerned that taking off from a stop or accelerating in 2nd gear (this is an SM420) would be struggle. I have 30.5 inch tires. However, I honestly can’t feel much difference taking off….and highway cruising is more comfortable.
That said, I am also planning a T5 swap (someday) and I figure the 3.38 will make OD kinda useless. But I like it enough so far that I might just step down in tire size if/when I get around to the T5 project.
