Here is my current 13.5 4wd setup for OCRC Indoor Clay...did some more dialing in after lacking some pace at Stock Nats.

Hope this helps, its for anyone running with the front top deck, and then I normally use the rear top deck which gives me a bit more corner speed...if there is enough grip. This also works for the plastic rear braces which plant the rear end some more.

For the diffs, if it was a more sweeping layout, I would say 15-slipper-10 on the oils, but I kept it lighter as the layout had lots of tight 180s.... plus I just ran out of time.

Chris Reilly: If you were to run mod 5.5 or 6.5 how would you change the set-up?

Kurt Wenger: I change the motor and pinion. Sometimes for mod you dial out a little steering but usually the same setup works

Chris Reilly: If you had a low traction track what would you change ? Our tracks are generally lower traction and bumpy.

Kurt Wenger: I would go to 3 hole pistons 35-30 oil with 1.4 front 1.5 rear. I would also remove the rear top deck and go to a plastic brace for more flex.

Chris Reilly: Thanks Kurt! Appreciate someone who has way more time on it than me. Will make the learning curve a lot shorter.

Source:

K. Wenger