Thanks for the clarification, either case I don't see the point.
I can't say about the propane but the point of Nitrous Oxide is it adds an enormous amount of oxygen to the intake charge, thus allowing more fuel to be burned...creating more cylinder preasure.
Cylinder preasure = power
610 ft lbs of torque is nothin' to sneeze at.
So you dyno this on an engine dyno or a chasis dyno?
What do those things have from the factory? Engine size/type I mean...