Pro tree chassis car, light (2350# loaded), 525 HP, 5.29 with a 3.31 stroke - 4.86 with a 3.60 stroke, 32" tire. I had everything in this car from 1.76 to 2.74. A 2.45 3 speed was quick, but would turn the tire and kill 03-04 reaction time and 60' often enough that I always had to have some in my pocket and then race the finishline based on how it left. 1.76 was a turd. 1.96 with a 4.86 = 9.52 worked nice on most tracks with an aggressive 4 link set up. As quick as the 2.45 but more consistent. 1.87 may have been a good choice but we never tried that.