Madison, you can raise the truck bolster higher in the frame to account for any given drive truck you might find if that's an issue for use of it. Width of any power truck is something to consider too.
That auction you were shown- the power truck in question is the same as the one I have here; axle spacing at 2 1/4"...close! The motor though sits out nearly a 1/4" from the outside of the wheel due to the nature of its design.
I'd truely suggest the gear drives I showed you...I doubt highly that your going to find any other easy way aside from another type of power truck power truck{mth/lionel?}...sometimes things are close to scale for the sake of the finished project...rivet spacing and patterns, windows, trucks, body scuplting...how exacting to scale is in the eye of the builder. 
