Do you have the zip ties installed between the rear bracket of the car and the rear suspension arms?
If not , to do this will maybe the easiest solution to your problem...
If I remember right , we use in former times the CVD's from a later yokomo buggie ( 870 , maybe) , but at minimum you have to replace the pins at the gearside of the CVD through longer ones ( 12 mm) and maybe you have to add some washers between the CVD shaft and the inner bearing at the rear suspension.
Then you have to rasp away a little bit of the balls of the CVD at gearside , so that the ball stays free from die allensrew inside the cup joint of the differential.
I cannot remember , if we did something against that the diameter of the ball on gearside is only 6 mm and not 8mm , maybe pull some small rubberrings over the pins....
But even with CVD's you have to use the nylon zip ties.