Even's instructions are correct for a 1/2 ton (3100/3200) truck. If your's is a 3/4 ton let us know.
3100/3200 Chevy trucks (and 100 series GMC trucks) were half ton models. They all had 6 lug hubs with a 5.5" circle. 3600 Chevy trucks (and 150...
[ATTACH]
You didn't say what year your 235 is, but this page 1954 Chevrolet Truck Shop Manual from the 1954 Chevrolet Truck Shop Manual says 450-500 RPM.
I'd ask the question "What is the minimum and maximum rim width for your 225/75/16 tires"
Did you ask Diamondback what rim widths are acceptable for their 225/75/16 tires?
Set the A/R pointer to zero before setting timing with a timing light. That way one can experiment with advancing the timing using the A/R...
Separate names with a comma.