[asid61]

Looks pretty good, although personally I just like using 1/4" or 3/16" thick for gearboxes and such (more thickness for press fits and counterbores).
Are you planning on tensioning the belt, or are you just going C-C? If you did a slight redesign, you could tension the belt like 192 did for their 2014 gearbox (look it up, pictures on CD).