For differential oil I always ran really light oil, machinist oil. When I was running carpet more often you want really stiff oil for the right side of the car and less for the left. I would run 80-100wt on the right and 60-80 on the left. Your mileage will vary depending on your track and if it has a banked corners. Make sure you nail the ride height as you want the car as low as legally possible without hitting the carpet during cornering.

@@OvalEdgeRC thanks. It’s flat track high grip blk carpet . That will give me good starting point. We run big block rules with 17.5 motor. Really appreciate info.

@@lloyderc Don't forget to tighten your slipper clutch all the way in, then back out a 1/4 of a turn or less. Also use aluminum gears for reduced rotating mass.

Yes any block would work, just know the rules for your track if it has a ride height rule.