It would be easy to bolt

the torque converter on the engine flywheel  or the PSRU prop flange.

I would suggest for something like that, what you want is a fluid coupling,
like used on old hydromatics, (pre 56) that make a solid lock up, not a
torque converter. Input shaft thrust washer thickness allowed for lock up
adjustment. The different size couplings which were pretty much universally
interchangeable  would allow greater engine size variables to be taken into
consideration. Of course, now all you need are several old (really old - 50
years or so old) automatic transmissions. At one time, these things were
like the old venerable flathead, pieces everywhere. Now, who knows?

jofarr, soddy tn

Yep I agree. The problem is finding one.