2 wire tach

[mtgoat]

I have a tach out of a 79 jeep cj with 258 6cyl.The tach has 2 wires coming out the back 1bare and 1 red this OEM from the jeep.I was wondering if I could hook it up to my 68 390 with Mallory ignition and 40,000 volt coil. I done a lot of searching just can't find what I need.Would apperciate any help.

[basketcase0302]

Don't know if would apply here or not-but most of the universal or older tachs had a switch that had to be set for 4-6-8 cylinders.
And I'm not real sure how a two wire tach would work either, as most will have a ground (usually black) / a green(negative side of coil) and a red / (switched 12 volt positive). Maybe someone else will chime in here soon that knows more about it.
Most would also have a white for the tachs internal lighting.

[mtgoat]

First thing I did was look for a 4-6-8 switch, the case in the back and the front trim ring are permently attached. Its a Thomas G Faria corp. Just trying to save some money. Thanks for the help ifanybody else has a thought would be great.

[Ranchero50]

OEM ford tachs for my '68 ranchero have two wires that have the coil positive lead going from the key switch to the tach, to the coil +. I have no idea how Jeep would have done it but I'd guess it will only work for a I6.

Jamie

[BobbyFord]

It won't read correctly if the tach came from a 6 cyl.