Maybe this will tell you something: Back a few years ago I was in the process of ordering a new Airgap form a prominent engine builder on the east coast. He asked me what I was running at the time and I was told to save my money, that andy improvement (if any) would be minor and not a cost efficient thing.
Not satisfied I called edlebrock tech and the technician I got was familiar with the old school LD340 and he told me the same thing. IMO it speaks well for old school technology.