71cuttyS

I remember seeing a thread of how to do it but now I cant seem to run across it. Can anyone help me and tell me how to get my tach working with HEI.

thanks in advance.

bbolds442

your tach should have a power source b+ and ground, also will need a reference for the tack, you will pick this up off the negitive side of connector or ground on the hei connector from the pickup to the coil. the reference wire on most am tachs is a green wire. good luck!
robert

Run to Rund

I assume that tach is the same as the side tach for a 66. You need a tach adapter to change the square wave to sine wave. When Olds engineering sent me a couple HEI's in 1974, they included the adapter so my 66 tach would work. Modern tachs (I have an Autometer) automatically work with either kind of signal. I haven't tried the MSD adapter but something of that ilk is what you need.