Tachometer Wiring

[Mustangmike]

With the modern "Air Core" technology type of tachs the needle is at whatever RPM the engine was when shut off.  I don't understand why.  But that's how they operate.  It will drop to zero by simply cycling the key and not starting the engine.

So his motor was at 1300 RPM when shut off.  If that's a hot idle it has an aggressive cam.  And when you grenade your motor at 7000 RPM, the needle will tell your wife what you were doing. 

Ahhh that makes sense.  The guy does have an aggressive cam in his engine.  He has more money invested in his engine than I have invested into my Fairlane and probably my Mustang too.

Thanks for the help.