315 ft long and 42 ft diam. with larger horsepower than 45000 Shp Seawolf. it would be about 8200 metric-ton class surface. assuming Reserve of Buoyancy of 10% typical US Sub, submerged displacement would be 9020 ton. Assuming half volume of it (like 4000 cubic meters) allocated for propulsion. Seems like 50000-60000 Shp plant is possible, and this could drive the boat with speed about 40 Knot at 60000 Shp.

Given the emphasize of high speed, apparently this kinda mimic Soviet deployment of P-705 Lyra (Alfa class). Cruising at such high speed tho, expect cavitation noise to be dominant.