which should i believe?

[bah]

i just hooked up my MSD digital window switch for my nitrous, and looking at the tach while looking at it it looks like its reading about 200 rpms or so lower than the tach says, which should i believe? although when i am at idle my tach usually says just a hair over 1k or so, but the window switch is saying its right at 800, which sounds about right, its tapped into the brown/white wire going into the icm and set to 1 cylinder

[FireShadow]

Re: which should i believe?

I have had a tach and shift light that both agree with each other but read 200-300 lower than the instrument panel tach on for years. My personal opinion is that chevrolet just altered the instrument panel tach to read idle at 1000 so it would look pretty or something. So it winds up displaying higher than what it actually is. Not too many cars idle at 1000. Just my personal opinion though.