Thanks Bill,
Tim asked me earlier how I knew it was a 283 heavy duty engine, and that is when I realized I made a big mistake and that it would have been painted grey instead of green. In '59 Chevy had 2 different 283s that they put in their trucks. Those 2 engines were the Trademasters(what I have) and the Taskmasters. These two engines were almost identical as far as specifications go, Same stroke, bore, horsepower, etc. But, the Trademasters were used in the light trucks and the Taskmasters were used in the heavy duty trucks, as you had said. In '59 Chevy also had the Super Taskmaster which topped both the regular Taskmaster and the Trademaster by an extra 15 horses at 175.
Thanks again.