We actually are almost done putting one of our old competition cars back together with a CB360 engine (free) in it. Not crazy power, but still 3 and a half times as much as it was designed for. Based on the gearing, it should do about 65mph at 8000rpm (well below what the engine can actually do).
The old style rear end of the car is a solid steel shaft with a keyway milled into it, and splined inserts pressed into the ends. Driveaxles are turner cycle high angle units with a pretty large amount of plunge for some large ATV that is excaping me right now. Custom length I believe.
For this year the new car is going to run a rear end from a Polaris Outlaw 525 IRS. Possibly going to have to modify the half shafts a bit, but we will be able to stuff longer driveaxles in the rear of the car, allowing us much greater travel.
Finishing up the new uprights, parts not shown are the spindle itself, which gets pressed into the circular hole in the center, and the studs that come out of the holes in the top and bottom.:
