A lot of it is track conditions. I've run a 14.20 at 99mph to 13.78 at 101 at LACR 3000ft altitude. It just depends on the humidity, temperature, barometric pressure, and wind. Your best passes come when the racing gods give you the conditions.
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92 GT, 4:10 gears, centerforce clutch, 6# powerdyne blower, bbk h-pipe, flowmasters