Vacuum question!

An LM1 is a very sensitive O2 sensor, connected to a gage, to say whther the collector gasses are rich or lean. IMO, to do it right, you need one in each bank, running simultaneously. Some places make kits like that, where you have one readout, and toggle between the two sensors. They are a cool toy to play with. The Demons by design react differnetly than a comparable Holley. They ar the same basic design, but taken to a further extent. My best advice is to buy a book on the subject, then grab some tools and go do it. Ignore what people tell you as opinion. Find it out for yourself what turnign a screw too far does. Learn what a smooth idle with a lumpy cam really means. It's the fastest way to learn for me. A fast idle doesnt wear parts. It does (at least to me) get irritating, can attract police, and wastes fuel. I'm finicky about idle..lol.