There is no such thing as a "Hudson" posi.
I bought a posi chunk (gears/posi unit) from a Dana 44 out of a 60's ac that the owner was changing out. I installed them in a 52 Hudson dana 44 rear. So look for a Dana 44 posi unit, don't see why you couldn't change the spider gears to 19 spline if you need to.
I talked with a parts company that handles Dana 44 parts and ordered the bearings from them, Just set it up like the info said to do. They supplied new bearings and seals that I used.
However, having done all that, a later rear end, say a ford 8.8 with disc brakes is what I would do next time. The axles are stronger and parts easier to get then the early Dana. A lot of info on the web about how to cut the housing down ---

I'll look at that option too. I've set up Ford 9" rears before, and those are very tough units (but a 308 would not put anywhere near that much stress on the rear axle). I like that the whole pumpkin comes out of the axle housing in one piece to work on it, and you can set the gear lash and pattern primarily with a threaded collar instead of shims. As an assembly, the 9" weighs less than competing axles because the axle housing doesn't have a big hunk of cast iron welded into the middle of it. But the 8.8" would be more than strong enough, and lots of them are available cheap.

Thanks again.