I worked on the timing today and was able to get a decent result. I set the initial timing to 4 adv, then put in heavier springs. With mechanical advance only, the engine pinged under heavy acceleration in the lower RPMs. I discovered my HEI distributor already had an adjustable vacuum advance, so I adjusted that until I got advance that didn't cause ping under load. I will keep trying to dial it in, but right now am more satisfied with how my truck runs.
This is certainly an adventure! I didn't know timing was such an art
. I hope my mileage goes up too because before I was very retarded (both ways).