I owned a Good Humor truck for a few years. This has to be the hardest service a vehicle could possibly see: stop sign to stop sign, 8-10 hours a day, 7 days a week, in mid summer heat. My truck was a ‘71 Ford P350 with a 300 straight 6 and the C4 automatic, and it had well over 100,000 miles when I bought it in ‘82.…