[Cliff R]

I have yet to see an 8.5 with bolt in axles. All of the units I've aquired here, truck or car used "C" clips.

The really late units, after 1987 or 1988 will have 30 splines instead of 28.

Many of the later units also used Eaton locking carriers, which are governor controlled. This makes them more difficult to detect turning one axle to identify them as a "posi" type. It takes several hundred rpm differential in axle speed to engage the unit so they act like an open carrier.

One of my customers installed a True Trac in his 8.5 and completely destroyed it on his first outing to the track. It was a very early unit, but had been in service for quite a few years with street tires and no drag racing. He contacted the manufacturer and they provided him with a later unit, which is supposed to be a stronger/improved version. To date it survives fine behind a 455 making over 550ft lbs torque.

I've been using an 8.5 in the Ventura for decades. The original posi unit ("S" spring type) lasted fine until I installed my first and full race slicks. Blew the spider gears to bits on the first outing. Installed a second nearly mint condition used carrier, it blew up on it's first outing. Went to an Eaton posi with Mosier bolt in axles, and it lives fine now for 10 years and many hundreds of runs with good traction, 1.6 60' times.

It gets inspected every year right before Norwalk, and I replaced the axles last year as a maintenence item.

As good as the 8.5 has been to me since we got all the good parts installed, if I had to do it over again, I'd have bought an aftermarket 12 bolt or Dana 60 and been done with it......Cliff