difference between these two cams?

I'd go with a 1.3/4 longtube or fenderwell, Those 26" tires might be a handful with that much torque, 28" would be better for 3.73 gears & 4" stroke.. Call & talk to Kenny at PTC converters, I would go with a 9.5", he can/will hook you up for a very good price. I like the M-1 single plane on the BBs.