Food for thought
Ideally the pinion yoke on the rear end and the rear output shaft of the transmission are parallel
Ideally the transmission will be down from center 2 degrees
Ideally the rear axle will be up 2 degrees from center (-2 )
Ideally means just that
You have options
I deal with this a ton with rock crawler jeeps and the like
Tyr to make the angles match so the trans and rear axle are parallel
Run a double cardan (3 joint shaft)
Some old Lincolns in the early '60s had double cardan joints on both ends (4 joint shaft)
I am no genius and this is all out of books
" As a general rule the maximum angle that a driveshaft should have is 3-degrees in a multi-shaft setup. More than that can put too much stress on the joint. Technicians should also be cautious of the driven member angle. It should be the same as the angle of the next to last drive shaft in your setup"
I could not find a picture of one of those old Lincoln driveshafts (which also had twisted splines)
Below is one I found from the IH8MUD forum