I'm pretty sure all the hot rod garden tractor pullers use old cub cadet rear ends.
Someone mentioned JD212 models I had one and was not impressed with the peerless rear end.
Find a JD 650 or 750 compact with the factory belly mower. We bought a 750 new and it has been trouble free.
I also had a 318 and was not impressed. I don't like the hydro on the dash and the Onan engines are not that wonderfull. You have to pull the engine to change a starter ! I like the 425 better and really like the foot hydro pedal design.
I mow with a F725 JD now and it is a good machine. Front mower and a foot hydro and really tight turning radius.