426 Hemi idle and vacuum leak detection

[hemi68charger]

Hello All,
Now that I have my 426 Hemi running somewhat good in the Daytona, it is time to fine tune it. In the old days when one didn't care about engine paint and such, one would spray some carb cleaner around a suspected area of a leak ( i.e carb base gasket, intake manifold gasket, etc. ). But, isn't WD-40 something I can use too that will increase the rpm in the event there is a vacuum leak source? I just want to make sure I don't have one before I press forward..

Also, in the event I don't have a vacuum leak, is it normal for the vacuum reading/rpm at idle to go up and down? I have set the curb-idle timing to about 15-16 (have installed two light springs). Then I started to adjust the fuel/air mixture starting on the passenger-side rear carb, then the driver-side, then back. I can obtain a reading of 13ish, but it will cycle up and down, never get it rock steady. The cam in the motor isn't far from factory spec. I don't know exactly what it is, but it isn't far from OEM stock. Then, I went to the front carb and did the same (the front carb's idle screw is set to completely close the throttle valves).

Ignition is a MSD6A with a Chrysler electronic distributor as a trigger with vacuum plugged since I have the light-spring curve kit in it.

Sorry for the constant questions; but one continues to learn......


Thanks..
T