rear end question

Just to point out the obvious, if you get talked into going LBP on the axle, you will also need to go LBP on the front, or carry two spares <gr>. So that's another project.

I'm just pointing out that you want to have a plan for the whole project, starting with deciding if you are going to drive it, and upgrade things over time, or if you are going to tear everything down and do it all at once. Experience shows that the first approach results in a lot more miles on the road, if not necessarily a show-worthy result; the second approach leads to a lot of carport ornaments and "non-running project car for sale" ads, and the occasional knock-out showpiece.

Sorry, wandering off-topic here...

My inclination would be to check out the axle, and if everything looks OK, just run it. If not, then you have the SBP/LBP decision to make, and others.