Here’s a link on setting your timing.
http://www.badasscars.com/index.cfm/...d=76/prd76.htm
I had a similar built motor to yours and lived at higher elevation like you do.
My motor ran best with 22 initial, 12 in the mechanical and 10 from vac advance. Had 12 hg of vacuum. I ran a modded Hei.
http://www.crankshaftcoalition.com/w...EI_distributor
At higher elevation you need to start the fire way earlier, hence the much higher initial. You also need to run your carb slightly leaner. And your tranny gear ratios or torque converter stall are somewhat critical.