wiring in a tach?

Question

on a 75 chevy, to wire in a tach do I have to use the TACH plug on the side of the distributor? is there another way to do it?

Answer 1

Yes, you have to use the output at the HEI at the side of the distributor to get the rpm signal. The other connections are straight forward, ignition power and ground. My suggestion to you is to use the proper locking connector that the power connector to the distributor uses rather than jamming a connector onto it. This way you are assured of a good connection. These can be found at an autoparts store or can be grabbed from wreckers. There is no other way to get the rpm signal from this type of motor so you are stuck doing it this way.

Answer 2

No, Not on this old of car. It is quite easy though. All you have to do is this.
1. Take your red wire (positive) and you can either be quick about it and just pull out an unimportant fuse (ex. cigarette lighter) and stick the wire into the plug then stick the fuse back in or you can wire your tach on its own fuse. Either way they both work.

2. Take your green wire and place it on the negative side of your coil plug.

3. Last but not least, make sure your black wire is going to a GOOD ground. If it is not grounding well, your tach might not work or will work eratcly.

HOPE THIS HELPS!!

Answer 3

your 1975 has a HEI system. next to the red wire pluged into BAT slot of distributor you will see a terminal marked TACH use a slide on connector onto that prong, connect to + side of tach gauge connect a wire to - side of tach gauge and run to a good ground.

Answer 4

yeah i agree with junior, thats the only way. feel lucky, those are the easy ones.

Answer 5

joes got it right