Originally Posted by SlowerOne

I ran a Dynamite and Reedy Sonic Mach II in mine. The Dynamite was on about 30deg at 68mm rollout and the Reedy on 35 deg with 65mm rollout.

The Reedy was better across the run, but initially I over-geared it at 70mm rollout. When I realised it was not revving out on the straight and dropped the ratio to 65mm rollout, it was better all round.

Every motor/timing combination is different, but I feel that 75mm is too high on this car. Taking the weight and the inefficient suspension into account (there's more wheel scrub and you have to slow into the turns as the car is more inclined to rollover in sharp direction changes) a lower rollout allowing the motor to rev and pick up speed quickly was faster round the lap. YMMV. HTH