MSD to factory tach adapter question
 

Has anyone hooked their factory tach to an MSD ignition box?
I've ready it requires an adapter from MSD.

I currently have the MSD 6A ignition box in my truck with an aftermarket tach. I already have the factory tach in the dash and would prefer to use it since I do not like the look of the aftermarket tach.

Any insight into this would be helpful.

Re: MSD to factory tach adapter question
 

the factory tach works just fine in my rig with a msd. i think the adapter thing is more for the later year tachs..

Re: MSD to factory tach adapter question
 

Do you just have it hooked to the tach output on the MSD box?

Re: MSD to factory tach adapter question
 

yep, box to tach

Re: MSD to factory tach adapter question
 

easy!

Re: MSD to factory tach adapter question
 

Looking for a bit of clarification here.
Few guys here have said that all they did when hooking up their FACTORY dash tach to an MSD system, is hooked the factory tach coil negative wire to the grey tach wire coming out of the MSD box.
Has it worked?
Some have said it worked for a month, then piled up.

I'm using an MSD 6-AL2 ignition box, MSD 8253 coil, and a MSD 85551 distributor.
I also just added a Brother's Truck 0-8K rpm tach dash, and the only 2 wires that go to it in the supplied instructions are, power, and coil negative.
The MSD grey wire is a positive, square wave signal...

Please help!
Thanks!

Re: MSD to factory tach adapter question
 

I did some more digging after I sent emails to Holley, and Brother's Truck. (Not holding my breathe for a reply)

Found this:

Re: MSD to factory tach adapter question
 

Dec. 24, 2023 update.
Hooked the factory GM tach wiring (brown wire) straight to the grey tach wire coming from the MSD 6AL2.
It works!
No adapter required.

https://youtube.com/shorts/gpsXwWqjt...vgjfUsaeUBxSZc