Case IH 350 quadtrack 1/32. NEED HELP

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I’m new here, and I don’t have a lot of knowledge of rc. Trying to do a conversion of an ertl toy quad track. Having trouble with getting my power, Ive got a Tamiya 3 speed gearbox with a small brushed motor, in the long run I don’t think it is going to have enough power, will only spin the tracks in low range, and drains battery rapidly. Does anybody know what I could use that would also sit in the small frame rails