Cid x VE% is probably the biggest factor for torque. (technically a 318 x 96% = 360 x 85% = 306)
Hp at 2,000 - 3,000 rpm is 38%-57% of torque.
That 318 is making similar low speed power as a stock 2bbl 360 but ya ain't gonna make same as a warmed over 360, but generally you should be running deeper gears with a 318 so should be comparing the engines hp at the rpms they be at for any given mph. Say 318 is at 3300 rpm while 360 is at 2900 rpm at X mph then those are the hp numbers that we should be comparing. So a lot depends on gearing which most leave as an after thought.