Did a few hours of research on the 518 and talked to some local HP trans type shops plus a few people that are experts from here

and, well ..

I am going to use a 727 with a gear vendor

Mock up with be with a shorty style 727 and when we get to the OD stage , the mount will have adjustment (not supposed to need any)

and make a torque tube then


More pics will be posted this week, made more progress