Dunno about the -360, but the -320 (in the PA28-161) produces 160 HP at 2700 RPM. That's 119 kW at 45 RPS. So torque at that setting would be 119.000/2.pi.45 = 420 Nm
Maximum torque isn't always reached at the highest RPM though. There may be an RPM below 2700 which produces more torque than that, but because of the lower RPMs, produces less HP overall. You'd have to consult the torque diagram of the engine for that. Not a standard part of a POH, I'm afraid. Have to find a data sheet for the engine.