Shade tree wild guesses on timing are fine for engines with all original equipment. The pointer and BB are there as a starting point, even if everything else was stock, which it obviously isn't. This one doesn't fit that category. It's WAY over-carbureted, plus if the exhaust is assembled anywhere near correctly, it's got enough exhaust scavenging to change the entire volumetric flow. Some pretty sophisticated analysis of the ignition timing curve is going to be required just to compensate for all the rookie mistakes that have been inflicted on the fuel and exhaust system. It's probably way too lean which is going to make it prone to detonation at the drop of a hat.
Jerry
