As far as posi's go for the 10.5" 14 bolt, about all you're going to find is the "gearless" lockers such as Eaton/Detroit, Powertrax/Lock-Right, and Yukon. I've heard about as much good as I've heard bad about them. My Dad had an Eaton in an 85 K30 and it gave us years of trouble free service. We abused the heck out of it too. After turning, you had to wait to get on the gas until you felt it lock in. If you didn't, you would get a violent jerk and a bang! when it locked in.
On the other hand, the ARB like Grigg has, seems to be a good option. Lock it whe you need it, open when you don't. It's probably a little more complicated than the gearless type, but on a truck that sees alot of street time and some off road time, probably worth it.
Chris
