Shouldn’t his vacuum advance be on the full vacuum port?
this a good description of what form of vacuum is required..
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Well, this ISN'T an "opinion", it is PROVEN FACT.
Ported vacuum advance adds a second acceleration timing curve to the engine, to help make ultra lean combustion more complete, at the cost of efficiency, cooling and fuel economy. The idea is to time the engine on the ragged edge to help raise combustion chamber temps top burn every last molecule of fuel, so no unburned hydrocarbons emit from the engine. If you have an engine with a functioning EGR valve, ported vacuum advance is for you.
Full manifold vacuum should be called exactly what it is, and what Ford called it decades ago, "Load Compensator". In an engine that does not have an EGR valve, combustion chamber temps want to be high, but not to detonation levels, as EGR engines are. To adequately burn fuels, a combination of correct timing and carburetor jetting is essential. The engine wants only ONE acceleration timing curve, mechanical, while at low to no load, can tolerate more timing for cooling, efficiency and fuel economy, so, we use the load compensator vacuum advance not to add temps to the chambers, but to add timing when the engine can tolerate it, idle, low load, high vacuum operation and cruise. "