A few hours spare over the last couple of weeks has got the adaptor sorted for the engine stand.
Closer inspection of the crankcase housing reveals its an aluminium machined block, not a casting. It will be interesting to get the aux end cover off and peek inside.
I got some steel blanks plasma cut. Ordered online to the exact size I wanted, including the flange:
Holes needed marking and drilling but the steel blanks were perfect and burr free.
Quick loose fit of the flange confirmed the marking out was close enough.
And the main mounting plate lined up too.
After tack welding the spacers in-situ I took it off the engine to put a bit more weld around each. With my welding I was not planning to rely on the strength of the fillets, but by weld No 28 of 32 quality was improving:
And final fitting, ready for a lift onto the stand:
Next few days should see the engine off the floor and onto the engine stand. Then its back to stripping the motor down.