Hi Terry, once the diffs, and engine are out, the tub shouldn’t be too heavy.
I saw an ad in a British car magazine called Practicle Classics, made out of tubing that had been radiused. This tip over jig, made from 2x6’s and plywood has the same profile as the advertised steel tube job. Getting tubing bent shouldn’t pose too much trouble. Or maybe the wood job could work.
From the UK. The autovip car roller
https://autovip.uk/basic-car-roller/
And some wooden design of similar principle.
https://www.youtube.com/watch?v=yuGf68o3tKY
Also found an ad for a custom rotisserie builder in Brantford his name is Stan
Tel 519-756-3817 prices starting at $1500