I think some where, might have been on here, I herd some one makes an adapter to bolt a 22 series moter to an SM420 who makes this? then you could use like 4.10 axle gears because of the way low 1st (7.05:1) and then the 4th gear would be like an overdrive but the first gear/4.10=28:1 combo would still be lower then a stock toy 5spd(3.93)and 5.29s=20.8:1which doesnt seem like a huge dif but it is once you add tcaces in
2.38x4.7x7.05x4.10=323.3:1
2.38x4.7x3.93x5.29=232.6:1
its like 100:1 lower! but I guess this would be trail only rigs:dunno:since the 420 has slow shifting.