I used to trip clocks on rear tires quite often. Used to ignore the 60 ft times for a while and just look at the 330. As long as the 330 ft time stayed the same, didn't get concerned. With equal 330ft times rear tire 60 fts were 1.21 and front tire 60 fts were 1.17. Obviously the slower the 60 ft MPH the more differnce it would make. Wheelbase would also be a factor. My wheelbase is only 106. When running the 727 transmission we actually had a couple 330 ft rear wheel times. The powerglide calmed the car down but, we also lost ET for a short while. Some lower rear gears fixed that. Never tried the aftermarket 727 gearsets.