I forgot to mention one important factor. My ignition is not stock. I upgraded to a DUI HEI distributor. Not sure if that makes a difference. Should I assume I can still advance the timing to get the same higher altitude benefits?
I live in Oklahoma but try to get to Colorado a couple of times a year with my stock 1981 FJ43. My practice as been to adjust the carburetor and lean out the fuel mixture as I gain altitude. It has worked with some success (steep or moderate grades at altitude put me in the very slow lane) and...