Tach to Dist

[Green79Scottsdale]

What kind of connection is on a factory distributor for the tach? My truck is the first vehicle I have owned that didn't have one. Truck in question is a79 w/400 sbc.

 

[bucket]

On the distributor cap, there's the big red ignition wire that plugs in. Right next to that wire is a spot for a tach signal wire. There's a proper connector that should be used , but a regular female spade connector works too. The proper connector can be bought new, or a used one can be found in any tach-equipped GM HEI car or truck, before they went to the small cap in '87.

 

[Green79Scottsdale]

Thanks Bucket. This is why I hate not having my truck at my house. I can't just walk out and look at it myself. I am looking to do a quick test on the tach from my cluster, just to see if it works. Probably just use a spade connector for the test, but find the correct plug for the real installation.

 

[bucket]

The only real problem with the spade connector is just that it can be hard to get plugged in, you can't see the actual terminal with the dizzy cap installed. With the right connector, you just plug it right in and you don't have to worry about it.

 

[cooter55]

For the tach, you need three wires. The trigger wire from the distributor(you can get the proper plug end from your local NAPA store for less than $5). You need an ignition 12volt and a ground wire. That's it.

 

[bucket]

There's actually a 4th wire too, on an aftermarket tach, for the back lighting.

Green: Tach Signal
Red: Ignition
Black: Ground
White: Lighting