10.50 index, 3500 pound NSS car, 45-55 passes the tires would start to slip, and become unreliable. This is with two different brands, 4 sets total. They were worth an easy 0.10 on the ET, but with that few passes, I will never use them again. We get around the same. However we get roughly the same amount from bias ply's of the same size, (29.5 x 10.5), before they're worn out. The car is heavy and seems to prefer to hit the tyre hard. We picked up around .15 in the 1/4 with the radials, car is more consistent and stable throughout the run, in my experience anyway  . HTH's 
'74 Challenger..9.46 @ 145.9 1/4, 6.001 @ 118 1/8 so far. 4023lb !!! # N/A, Marsh performance 655ci, Indy Maxx, T/R, Indy 600-13 X's, Street legal, pump gas, full interior, Cal-Tracs, mufflers, 3:73's and real 10.5 radials.
9.51 @ 142.4 1/4, 6.003 @ 114 1/8 with our old mule KB, 572-13, 580 wedge.
RHD '68 Barracuda Fastback 323ci street/strip. Best ET 13.88 @ 99.03
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