I have a 1978 fj40 (on paper) on a frame and with a body tub of a 79 or later. Go figure! I live in Ecuador. Of course that means it is a 'General Population' vehicle with a 2F. No computer, no emissions, no a lot of things. I have been living at 6000-8500 feet but I am am at sea level now and the spark knock is horrible. I need to figure out how I can get home with pistons and valves still working. The carb is an after market knock-off, probably from China, and the distributor may be an older version because it has a plastic cap that screws over the vacuum advance adjustment. When the new carb was installed, the jets were not changed for the altitude and it was gutless. Here it runs good, except under load. Any advice? Can the adjustable vac advance do any good? I have 2 days to get this thing operational enough to make it home, and it's a hard ride for this horse.