For a stock 1987 th700r4 automatic transmission what is the safe range for horsepower/torque? From what I've read I think 300-320hp /300-369ft/lbs is ok... but I have very little expeirience in these matters. Also what is the difference between a 1987 stock th700r4 and a performance option th700r4 transmission?

I dont know the difference on teh trans types. Maybe the torque converter? I know the Z28 and what not had a higher stall. But anyways yea I believe the torque limit was like 370 or something like that.

In most cases the (1988-early 1993) will take not much more than the stock output of the engine. If the torque converter is changed to a smaller size (9.5" & apx. 15-17 lbs. lighter), this will reduce the shock of the heavy torque converter (12") on the gear train, thereby increasing the longevity. If a Trans-Go Shift kit or Performance Shift (with accumulation) is installed along with the smaller diameter torque converter, now the transmission can handle even more horsepower & torque , and live. Now if you build the unit correctly (latest updates, stronger sunshell, Borg Warner Hi-Energy clutches, Corvette servo, turbulator low drag steels, etc.), it can now handle about 525-550 horsepower reasonably. If you have any questions concerning this, call me.