Author Topic: Wiring a Tach on a TH400  (Read 2145 times)

Offline RGSMS

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Wiring a Tach on a TH400
« on: February 17, 2018, 01:33:00 PM »
Just got a new gauge cluster and it has a tach on. It (my old one never had one). I was wondering how to wire it from trans to gauge.


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Offline Rapid Roy

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Re: Wiring a Tach on a TH400
« Reply #1 on: February 17, 2018, 01:56:33 PM »
Welcome to the site
1974 Cheyenne 10 LWB STOCK 350 W HEI /TH350/AC/4 BBL Quadrajet
Mopar by Birth
Chevy by Choice

Online bd

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Re: Wiring a Tach on a TH400
« Reply #2 on: February 17, 2018, 02:06:05 PM »
A tachometer (tach) registers engine RPM so has no connection to the transmission.  Pink to 12-volt ignition, black to ground, brown to the negative terminal of the coil (the TACH terminal of the distributor if HEI).
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline RGSMS

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Re: Wiring a Tach on a TH400
« Reply #3 on: February 17, 2018, 09:08:24 PM »
Ok awesome thanks guys


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Offline 75gmck25

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  • 1975 GMC K25 Camper Special, 350/TH350/NP203
Re: Wiring a Tach on a TH400
« Reply #4 on: February 18, 2018, 07:38:38 PM »
Most auto parts stores sell the correct terminal that plugs directly into the tach connections on an HEI.  You need a connector similar to this one.  https://www.amazon.com/American-Autowire-500205-Distributor-Tachometer/dp/B003VXLOSU

You can make a female spade terminal work if you have to, but it is only kept in by the friction of the metal tab.

Bruce