You need the '82 and up T-5 flywheel.I believe they all used the 8" clutch. That will bolt up to the stock 9 1/8" S-10 clutch with no modification. The T-5 flywheel is lighter and has the weight concentrated to the outside ring so it will idle like a heavier flywheel but spin-up or rev faster. Feel free to lighten the ring a bit to compensate for the heavier clutch.
The total apply area of the 8" clutch is 30.56 in² per side. The 9 1\8" clutch is 41.62 in² per side. The clamping force of both clutches is close roughly 100lbs higher for the 9.125" clutch. which gives the 8" clutch slightly higher force per in². The fact that the larger clutch is holding from a 0.5625" leverage advantage I give the 9.125" clutch an over 60% increase in torque capacity over the 8" stocker.