kandacarlson -
Your timing probably drifted slowly due to parts wear. In addition, the NissanGorilla may have had too much moonshine the day he set your motor.
FWIW, setting the timing an additional two to four degrees advanced can improve performance/economy over the stock setting. OK, it may not work on *every* vehicle. But there are enuf positive reports that indicate that it may be worth a try.

dave and xtoy - gotta try it on mine someday