8.75 Sure Grip spider gears break

Thanks for both videos, was entertaining.
I can't recommend a replacement but i think the clutch is to harsh for what you are doing. Straight line drag racing....only a spool is better!!! For what you are doing you need the traction device to allow some slippage on the inside tire, but not act like a open diff.
I guess with shims You could make that "clutch style" lose a little bit of its grip to get both tires around the curves stuck to the ground. Probably be easier on your tires as well.