The HO52 and 72 rearends use the same 3rd memeber, other than gearing, regardless of single or dual wheel. The 5.13s were pretty much exclusive to the 1 ton, though it was offered in the 3/4 ton in some years. There also was a 3/4 ton 4.56 duallie rearend. Either way, the 3rd member is a direct swap.
You mention athe wide gearing, are you using first gear to take off? If so, try using 2nd instead. First gear on that trans is a very deep 7.05:1, and is really meant more for taking off with a heavy load.
Here's a video of a truck with a Ranger overdrive coupled with an SM465. The shifting part of the vid istowards the second half. Niow, that's using it as a gear splitter. You wouldn't necessarily have to drive it that way. You could just sput it in overdrive and leave it there.
At least it's not like this one!
