Assessing two T221 cases

[Short 3/4]

I need to reseal my leaky T221 transfer case that I had completely rebuilt in the past using the parts from a couple different cases plus some parts off of eBay. It works okay, other than of course being very loud (probably not helped by the mismatched gears). A few years after I rebuilt it I came across another case from what looked to be a very original truck being parted out. I had high hopes for this case, as the transmission out of the same truck was one of the tightest SM420’s I’ve ever driven. I installed the new case long enough to verify it worked, then removed it and put it on the shelf as a spare.

I’m now in the process of deciding which case to put some time and money into. In the pictures the previously rebuilt case is the one marked 65. The newer to me one is marked 66.

My initial assessment shows both having slop in the input shaft. One is about 1/8” while the other is around 3/32”. What is considered acceptable? There is side to side movement of the gears on the counter shaft. One is .010” and the other is .030”. What is considered acceptable, and how is it adjusted? It also appears the gear on the 66 countershaft is installed backwards. What other things should I be looking at? The gears in both cases look to be in good condition.

Of course any discussion of 221 cases is not complete without asking about parts sources. I know seals and bearings are easy, but how about hard parts. Any companies or members parting out cases?

Thanks for any help and advice
Tom