HPI Rush electric conversion - motor mount

I'm converting a HPI Rush R/C car to electric and needed a motor mount - nothing seems to exist so I designed this one.

It mounts to the holes which carry the screws for the brake pads, and to one existing hole in the chassis.

Designed for a standard 36mm diameter motor.

It's a bit of a dirty hack in TinkerCAD because I'm very early in my journey doing 3D design, but it works and it fits well.

The Mount_v5 fits the stock spur with slipper plate etc, like this:
https://www.ebay.co.uk/itm/134169058665?hash=item1f3d195d69:g:5JwAAOSwz5ViysG8

However in this case, the dog drive hub will slide too far down the shaft and interfere with the motor mount, so I cut two short bits about 5mm long off a 2mm allen key and used those to pack out the grooves in the hub to give it a 5mm standoff from the dog drive.

The Mount_v5_savage_spur fits an aftermarket dog drive spur/pinion set such as this:
https://www.ebay.co.uk/itm/174775340298?hash=item28b16c0d0a:g:1YQAAOSwuKRgpmEo&amdata