A little more progress.
i had to try to make a hub for the rear of the front engine. i used a bit of 1/2 inch plate , tough steel ,and machined it to have a recess to match the back of the crank ,then 4 holes for the connection to the crank ,then a hole in the middle to take the spigot bush out of the original 3 leg coupling casting .
it all went quite well ,and now you can see a rough idea of how it all goes .
next thing is to finish the 4 holes with a template to keep them true, drill the 3 holes for the ring ,and tap them M12 1.75 so they don’t need a nut on the back .so keeping it all as slim as possible .i still have to clearance the area on each hub for the other sides bolt heads.