Morning DON!
MATT - Yes, several models of green tractors used a u-joint to couple the engine to the 15U hydro unit and the drive shafts are rather short lived. My Buddy got a new 317 around 1982 and I think he's on driveshaft #4 now. And they're expensive, well over $100 now. And from what it seems the new ones available now last about half as long as the original ones did.
Torque retention lock nuts, either nylock or Stover-type deformed thread versions are single, maybe two use fasteners. Even the bolts should be replaced with the Stover-type, not required on the Nyloc applcatons. Nylocks should not be used where heat is present. The heat softens the nylon and they lose their grip on the bolt. Even Lock-Tight shouldn't be used in hot applications. Split typelock washers, or in some cases internal or external lock washers work good in some applications. But on rag joints I'd use a flat washer against the rag joint and a split type lock washer against the falt washer. Plus there's also safety-wire and on some applications a small stamped flat plate is used to secure nuts & bolts where the corners are bent up against a flat on the hex head nut/bolt.
DAVE KIRK - Thanks for explaining the science behind carb selection. It's interesting the way different engines respond to different carb sizing. The last "Big Truck" I drove really wasn't THAT big, had a 478 cid V-8 gasoline engine, IHC of course. It really wasn't "Governored" like some truck engines with a maximum speed governor. It was just choked down with this silly-looking 2 bbl HOLLEY carb like you'd expect to see on a small less than 300 CID V8, 283 Chevy, 289 Ford, etc. That engine would pull like a locomotive to about maybe 2000 RPM (no tach) maybe a bit more, then you kept your foot to the firewall for a while longer and let it spin up to 3000-3200 and shift up a gear in the straight 5-speed. RPM's drop to about 2000 again and you let her spin up to 3000+ again. No vacuum gauge but I'm sure it was pulling 6-8 inches of vacuum at full throttle @ 3000 rpm. I was always amazed that the tiny 1/4" OD fuel line could flow 20 gal of gas an hour running 60-62 MPH when I was getting from 3 to 3-1/4 MPG. Expensive truck to run now days!