I don't think the axles will stand up to more power, especially the front axle having to transmit all the power to back axles too. The pitch of the crown & pinion in these axles is quite small. And I have stripped the teeth from the very front pinion before. The last time I ran the junk740, the driveshaft knuckle between front axle & trans broke.
This model desperately needs a transfercase between front & two rear axles with additional reduction... too bad the model design doesn't have the space within to do so.
