OK, my worst fears have been realized. The gearbox change will call for major modifications. Time to retreat to an easier plan. Right[sm=drowning.gif]. Experience has taught me that when confronted with a tough problem, come up with an overly complex plan then get a government grant to pay for it. Sooooo.
Had to do some trimming on the lower hull. When complete, it will call for a slight non-scale feature but it will be minimum and should be barely noticable to most. Plus it will be on the lower hull.
Once the battery box and all the internals were out the chassis was completely flexible so I cut to shape a length of .060 (that's 1.5 mm for the civilized world) 6061 T-6 aluminum. Cured that in short order. I actually now have perfect axle placement as can be seen in the pic's.
I still have to fit the drive sprocket which will be tricky but doable.
By the way, the gearboxes are for a Walker, which has a 1/4" longer output shaft than the Tiger, et al, gearboxes.