Just a couple of questions on how to set idle mixture screws with a vacuum guage. Should I leave the air cleaner on or take it off? I am using manifold vacuum for the vacuum advance so when I hook up the vac guage should I leave the advance on and put a tee fitting in or should I disconnect the vac advance and just use the vac guage? Also should I turn up the idle so the vacuum guage stays steady and if so at what rpm should I put it at

The rule is to leave the air cleaner on but I never do because of work room. You do need to have the vacuum advance hooked up so use a tee. As far as idle speed, try to tune at the intended idle rpm, it can be a pain with a choppy cam.

I usually take it off until I get it pretty close to dialed in, then put it on(while the guage is still hooked up, and tweak it again, then loosen or tighten the holddown bolt to get the best possible vaccum reading after that.

Some say I'm a little too much of a perfectionist though... :D

I purchased a wideband meter a while back, and I finally tuned the Demon with it. Here's what I found:

1. Less than 1/16 turn on the mixture screws made a huge difference in A/F ratio, especially when lean. 1/16 turn goes from 14.0 to about 16.0 on the meter.

2. When I finally got the mixture to be 14.5-15.0 at idle, putting on my 14"x4" K&N filter made the mixture go down to 13.5, a full point.

Bottom line, a vacuum gauge or tach will get you close, but not exact; and ALWAYS set the mixture with the filter on!