Tachometer question
 

Hey new to the fourms and a new mustang owner. Well here's my problem, I bought a 92 Mustang GT and the stock cluster reads 4k rpm's at all times and the speedo reads the total wrong speed. The other gauges (Oil pressure, fuel level, etc) seem to reading fine. The previous owner must have installed a aftermarket tachometer and shift light then snipped the wires before selling it. The wires are still sticking out of the dash, im assuming still connected. Does the after market tachometer override the stock?

It shouldn't override the dash cluster tach,
more than likely the after market tach was installed after the dash one quit working.
Unless they disconnected it, but then I would expect it to read 0 all the time.

Well i spliced the wires and added a tach.. They were still hooked up and I figured out why the speedo isn't reading right, he put in 3.55 rear gears and didn't correct the speedo gear.

does it have an aftermarket ignition box such as msd??

It does not sir.