Had the car at the track a few days ago and had some issues putting the power down. The slightest bit of steering input while applying the throttle and the car came around. I tried a ton of things including making the wheelbase shorter and adding weight to the rear end and nothing worked, I felt no difference.

I think it was the gear diff I had in the car with 4000 wt oil. I stood on the track and watched it and noticed the car diffing out a bit the around it went! Even when it did hook up and weight transferred to the rear the car wandered badly down the straight. Unfortunately I didn't have time to throw the ball diff in it and test it. That will have to wait for another day.

I am looking forward to seeing the difference and trying to figure out the problem. If the ball diff cures the problem then I want to try the gear diff with something like 20,000 wt oil to see what that does.