Chip, the timing plate seems to be integral with the timing cover, I don't think its moveable, but I'll have another look. And the engine is likely original to the truck, as all the brackets, the carb, distributor, and casting number put it in the correct year range. It has been out of the truck and repainted and had unknown work done on it. Some of the previous work was of questionable quality. The carb. fitting was stripped, a worn out valve cover gasket was reused with silicone, the list is endless.
Josiah, using the original timing mark doesn't put any cylinder at top dead centre; it's only approximately 120 degrees off. It would be interesting if it did however, as you state, the I-6 fires every 120 degrees.
Fred
