Well jft69z the problem is finding a 12-bolt rear end or a 8.5" 10-bolt rear end that is in the price range of just replacing the parts on my rear end. I've called many junk yards in my are looking for a 12 bolt rear end and most done have them. If they do have them they want at least $1500 (non-posi) for the rear end and then I will have to convert that rear-end. The cheapest 10-bolt posi rear-end I've come across was $1000 (not even sure if it was an 8.5" 10-bolt) but I would have had to get it shipped to me. With my current rear end (with me spurging on parts) I am looking at about $1100-$1200 installed and that would include a "high-strength" alloy axle kit, richmond gear ring & pinion set, the Detroit TruTrac diffenential, and the miscellaneous thing like fluid, shims, and bearing. Couldn't speak on which rear end is more durable or better, simple because I lack the knowledge to make a quality case for either. To be honest I didn't even know a 10-bolt posi rear end was possible until reading post in this forum. What I can tell you is that I have no plans to race my car, but I do plan to rip up and down the highway every chance I get 😁.