I can't add much to the question of unleaded gasoline for your truck. My only experience with 'unleaded fuel' was a '54 or '55 235 engine in a truck that used propane fuel, and there wasn't a lot of experience with that fuel at that time. The head was good for about 10,000 miles, then a valve job. After the second head (third valve job), we put in hard seats. I lost track of the truck after that, but hard seats seemed to cure the trouble. That truck ran loaded all the time- it was a propane delivery truck, and the tank was pretty much a full load, even empty. I'll defer to the wisdom of others on this question.
Harvester
