Seat size? Driver size also can change it a little. We typically mount them 8 1/2 from the axle to the top of the seat and about 4 1/2 of inside edge of inner engine rail. If running a Med or Large 2.0 go 1/4"-1/2 higher.
Did the RF Spacer get taken out from first scale to second?
During your practice season did the LF hit any disc blades?
When on the scales lift the rear end and spin axle 180. Those Hoosiers can be very out of round.