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MSD / Tach connections
Ok I took the 73 mustang vert to the Mustang Day and show event in Charlotte last week. I took down on dolly since I have not driven but about 30 miles since getting it going and the PB booster is leaking and not working.
Now, I have never gotten the stock tach to work on the car. I even changed it for another and it did not work. I have the MSD tach adapter they said to get and think I have it hooked up correct.
I am sure others have this set up can someone get me some pictures of how to hook this thing up to work, lol. I get lost in wiring diagrams I need pictures and instructions like hook to yellow with with black stripe coming from dash, etc.
Is there a way to test tachs on the bench? I have like 5 or six and do not know if any are good. The PO put the MSD on and I added the Tach adapter. I did find a wiring harness that was not cut anywhere and the car has the following.
Tach and center gauges.
Convenience Group
Air Cond.
351 C H code with Eldebrock Performer 2 - V heads to 4-V manifold and holley carb.
Tilt column
Long console
I have added big ground strap from engine block negative battery connection to the frame and also another from engine to shock tower to make sure I have very good grounds. Every connection in the harness was cleaned with steel wool and all grounds have bare metal and clean.
The car starts right up and runs great just no tach.
Another thing is that the speedometer cable is not long enough to get to the back of the instrument panel needs probably 3 more inches. I have heard that there was some kind of add on to the 73 speedometer cable this car does not have it.
My dash lights do work, turn signals, flashers, wipers, radio, seat belt buzzer and light, etc. Just need tach and speedo.
The pics were made when going back together.

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When a man is in the woods and talks and no women are there is he still wrong??
David, I would say to send one of those tachs out to rocketman and have him convert it to work with the MSD. I had him do mine and it works GREAT!! He does awesome work.


1971 Mach 1
408C Stroker
C4 w/3,000 stall
8.8" Rear w/3.73's
Disc brakes all way around.

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Simple way to test a tach: put it on your fender. Remove coil + lead and attach to male bullet out of tach. Wire the female bullet out of the tach to the + side of the coil. Start the car and monitor the tach.

Let me check your shorts!

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... and if the car won't start, the tach is bad Smile

That said, I've never had an issue with the MSD tach adapter when wired properly. Use the 8920 and wire per the current trigger diagram.


(04-16-2018, 11:58 AM)Hemikiller Wrote: ... and if the car won't start, the tach is bad Smile

That said, I've never had an issue with the MSD tach adapter when wired properly. Use the  8920 and wire per the current trigger diagram.


hmm that is what I thought I did. Will have to go check tomorrow and see if I did something wrong and will try the midlife tach test also.
I actually want to get rid of the MSD cannot use stock air cleaner and the one on there now shorts out a couple plug wires unless I put a sheet of thick plastic under it while running engine. The PO had put it on and did not send the stock distributor with it I now have one. Just too many projects to get into that now.

When a man is in the woods and talks and no women are there is he still wrong??
I agree with Kevin, I was having problems with my tach sent it over to rocketman. He is reasonabley priced and thing works great with my MSD now... I ended up mounting my MSD under passenger seat which keeps it cooler and looks clean.
While the world of electronic issues is best not touched by me. the question about the speedometer cable was something I dealt with recently. I will have to look for my notes/order for a new cable but you are correct. I think the 73's went to a two piece cable but the one on my car had already been replaced with a one piece - albeit one that was too long and was for a manual transmission. I will see if I have the measurements for the one I bought that was shorter but worked fine. Check how it is routed. I thought the one I bought was too short but a little rerouting and it's fine. I know I bought the "concourse correct" one from one of the suppliers.
Here's a thread with good information from the "regulars" about the speedo cable.
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