[Cepheuz]

if you achieve your target speed and load, i think leaning the mix would be benefitial

can a person simply make a meter devices to inject air into the manifold, possibly trough the brake servo vacuum line?

tap into the ignition vacuum advance, the fuel enrichment and a plenum vacuum, when the vacuum advance is activated and the enrichment is not open the vacuum to the plenum and it will enrich the mix

then you would have a normal lean mix that doesn't hinder acceleration or load and you can adjust the lean mix even further by metering the leak amount

it's just right now an idea, but i think a plausible one