The RFM Part 1 Section 4 has the answer.
1. Power required to hover OGE Figure 4-8 (in shp)
2. Power available CT58-140 engines max continuous or takeoff power Figure 4-100 (shp)
3. Indicated torque vs engine shaft horsepower 100% Nf Figure 4-102
So assume sea level standard day, nil wind, 19000 lb, power required 2260 shp (1130 per engine).
Min spec engine will provide 1240 shp continuous or 1390 shp at takeoff power so that's OK, although of course the transmission is limited to 1250 shp/103% torque per engine at takeoff power and 1050 shp/86.5% torque per engine continuous.
Indicated torque will be (1130 shp) 93% per engine.
For ops above 19000 lb go to Supp 15, where the engine power available charts 15-4-8 to 15-4-12 show torque not shp, and Fig 15-4-14 has the shp to torque conversion for both 100% and 103% Nr.