So as you can see at about 3,000 tachometer RPM, the engine is only at 2,690 RPM (10.3% error), and at about 4,000 tachometer RPM, the engine is only at 3,570 RPM (10.75% error)
Let's do some simple algebra
The trend lines show the equation RPM = 1000x+200 for the tachometer (virtual), and RPM = 880x+1810 for the timing gun (actual).
Plugging in 7,600 RPM into the timing gun equation (what my actual redline should be), and we get 7.4 for x. Plug this value into the tachometer equation, and we get [evil voice]dun dun dun[/evil voice], 8,322 RPM, which, you guessed it, is about where my tachometer redlines (as shown on the previous page).
Well, the lack of an explanation as to why my car is so quick still remains. I need to pull some valve covers and see what cams I've got in this bad mo-chine.