Dwell angle of 28-32 degrees is fine. I think the 6-cylinder specification is 28-35 degrees, but 30 degrees is an all-around standard dwell figure for anything with 6 or more cylinders, and not a racing engine. Don't worry about equating dwell angle and point gap beyond that a larger gap gives lower dwell angle. Also, set the timing after you adjust the points. Its pretty hard to do otherwise with your engine, but sometimes setting timing is overlooked.
Regarding timing, larger point gap (lower dwell angle) advances the timing, degree for degree. Decreased gap (higher dwell angel) retards timing, also degree for degree. You might find that advancing the timing 3-4 degrees will make your truck run slightly better at your altitude- that's what the octane selector is for, but don't overdo it.
Harvester
