Chuck,
C-6, correct.
Mine gets 400 plus hp to the back tires from about 2600 rpm up to the 5700 rpm redline. Torque doesn't seem to drop below 460 ft-lb or so all the way up, with lots more at lower engine speeds.
With a stick and a live rear axle you should be getting a
much bigger percentage of your engine's output to the back tires than I do. Automatics & Jag rears are known for eating some hp.
This leads to the question if a better tune would help, or if there is a restriction to output such as mis-matched engine parts, exhaust or air filter.
I can put Victoracer slicks on and still spin the tires at takeoff. Street tires, no problem
Maybe you are already using slicks?
Tom