Hi Madmower
I admire your expertise and commitment.

I would like to say something on that gearbox.
I guess it is a 5-speed Tecumseh Peerless box.
There must be heaps of those available: -

LINK: https://www.ebay.com/itm/222850204497

Please keep us informed.
I'm sure you have already helped others.

Cheers
------------------------
Jack