I put a clutch in my 1000 Feb 2016. See my thread here
http://www.onlycubcadets.net/forum/s...ad.php?t=43135
I sent my drveshaft to Jeff in PA and he made me a new one. He may have kept the measurements of the original shaft I sent. If he did he should be shoe to make you one too.
My tractor had one flex coupling. I put it back the way it was from the factory. The serisl number shows it was made in August if 1977. I hope this helps.
Bob