[mnunn454]

I hear 4 different pieces of this question:
Do I want posi or not?
Do I need the strength of a 12-bolt, or will the 10-bolt be strong enough?
Do I have to have 5 lug axles or am I willing to live with 6?
Do I want rear disk brakes bad enough to swap in the whole Caprice axle?

I'd start by ranking these factors in order of which is most important, and then try to tie a cost to each. Rear disk brake kit for about $400-$500, Eaton Posi for about $400 (10-bolt or 12) plus $300 to $500 for setup (unless you do that yourself), Set of new 12-bolt axles for about $300 to $350 (once you pay for new studs and shipping).

Were it me, I'd stay with the original 12-bolt housing and add 5-lug axles. I'd then add a posi and rear disk brakes later, as needs dictate and resources allow.

If you can find a good 10" posi with disk brakes and the gearing you want for less than $500, then I'd go that way as long as you can install it and it'll handle your torque requirements.

JMO.