Cheers, yes I did mean VG... apologies.
and yes, the case of every Nissan manual box I looked at did not have a removable bellhousing, however the VQ auto for the V8 does, which makes it a little easier to play cut and shut.
That said:
"Good news is, if you're going to make a custom bellhousing, you've got your pick of boxes to handle the torque"
is only this:
"get a custom bellhousing and choose your tranny."
put more eloquently.
So the list expands from "does an RB25 or VG30 box come close?" to "supra 5 speed, this, that, the other" and now "getrag six speed"
Still, at least this go kart should trundle nicely when we're done... if I can figure out where to put the seat...