Spun mine in increments of 20, up to sixty. No smoke, BIG DIFFERENCE in off the line performance. My truck always felt as though it was wheezing, just off idle, with lots of noise but no power. Spinning the wheel made the truck much more tractable in stop and go driving. No fuel mileage decrease, either. Next I'm going to slide my stock plate forward. Just haven't gotten around to it.
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'96 Regular Cab, 110K, SLT, auto, 3. 54, Vista topper, Pillar-mounted Autometer Boost/Pyro, starwheel spun