Phazertwo, I'm glad we found you. Now we can get info straight from the horses mouth. Depending on the size of your jumper cables, that may have been a limiting factor in getting power to your motor.
Volcom - I didn't realize winches drew that many amps. Considering your standard alternator puts out 105-145 amps you can kill your battery pretty quick if you aren't careful. Sounds like you have to gear down from the motor to the compressor which will cause your motor to pull less amps, but in turn lower your rpm of your compressor resulting in less CFM.
Phazertwo, let us know what your revised design entails. 
You are correct that the size AND LENGTH make a big difference. We tried two different length of the same cable, (I think it was a 5-7ft difference) and the difference in the amp draw was quite surprising!
I am heating the garage now. Should have some info for you soon.
I had no idea that this many people would be into this!
PZ
