[dmjlambert]

OK folks, thanks. The engine was rebuilt a couple years ago with 1995 crate motor heads and GM HEI distributor and other components stock. I measured the circumference of the balancer and divided by 360 and found the marks on the timing tag are indeed 2 degrees each. The marks on the timing tag are "A 0 R" and other engines have "Before 0 After".

I detached the vacuum advance hose, plugged the port on the carb, set timing light set to 4 cycle and 0 advance, blocked the wheels and set the brake and put the truck in drive, verified with the timing light's tach function the idle is at 600 RPM. The timing mark shows 3.5 marks or 7 degrees before. The tune up sticker for this truck calls for 4 degrees before. It is in poor condition, but enough of it remains for me to figure out which new sticker to buy. So, it appears the timing is a little advanced.