In my stock 83 delta 88 with a 307, the original transmission got 175,000 HARD miles before the reverse took a dump. The one I have now I am ruthless with. It's a completely new transmission that is built to H/O/GN specs. This thing has been down the dragstrip numerous times at WOT, idles around town and runs at 95+ mph on the highway, not to mention burnouts, powerslides, light neutral drops, and everything else I can think of to blow up my 307. After 4,500 miles of driving like this, it still shifts hard enough to snap your head back, and when the TC locks up in 3rd gear, it'll shove you back in your seat. I'm expecting this transmission to outlast the engine.
Buddy of mine has an 81 delta 88 (3800 lbs) with 3.73's and a mild (350 HP) Olds 455. Runs 14.3's at the track and is using a stock 200R4. No slipping or anything, and this is with slicks and burnouts at the dragstrip. It's his daily driver and he gets about 4,000 miles a year on it.
Like I said though, get it out of a granny car, not out of a high performance or fullsize car.
