I run a fair amount of SLR with my 572. 10.535 SLR with 10.5Wx31 (w/tubes). Car weighs 3340 when not weighed down for index. 60ft with no weight 1.25-1.26, with weight and throttle pulled back 1.29-1.30. Consistent with-in .01 through out the day on foot brake and no rev chip.
Doug