Hey guys, I've got a 71 sportsroof(fastback - base model), that has a clock/speedo cluster, but it also has the water/oil/volt gauge bezel+gauges on the consol(all factory). I was wanting to swap in my tach/speedo cluster. So, I am needing a 'dinosaur' guru or two to help me out. Thanks guys.

Here is the kicker. as far as I understood, the tach/speedo cluster came with the oil/water/volt gauges, and a different harness layout. The clock/speedo cluster had dummy lights for the oil/water/volts, and not a sweep gauge.

So, I am starting to believe the clock/speedo cluster was swapped in by a previous owner, as my consol has a clock as well*right infront of the shifter boot*.

Now, here is the question. Could a person swap out a tach/speedo cluster, for the clock/speedo, without changing the rest of the harness?

Are there any other tell-tale signs i could look for, before just ripping the dash off, to find out if the cluster will work? It was the apparel package '71(nasa hood/front&rear spoilers/decals/mag 500's/hd susp/clutch w/4v 351c, and 3.25's out back).

I really don't want to rip the dash all apart to look and make sure the harness is compatable, unless i absolutely have to. If it isn't the right one, I need to find the proper harnesses(three of them, if i recal properly).

Anything else any one else can think of? When the car was purchased, it was dressed up, and sold as a 'boss 351'. Being it is only one letter away from being a boss on the vin, i can see why someone may have believed it, but it is not. It's code is 1F02M(fastback), not1F05M(mach) or 1F02R(boss).

Thanks for looking guys. Hopefully I can get some helpful info.

 

A quick and dirty was to do this is to replace the clock with a tach. You'll have to hardwire the tach but that's not hard to do. Another thing is that not all of the lights on the back of the clock line up with the same position on the tach so the printed circuit won't fit perfectly. However a couple of the lights are in the same position so it will stay attached and give you some light at night. I did this exact same conversion back in '81 so I know it works.

 

No, see I am sorry for being missleading. The car has the speedo/clock cluster in it at the moment. I also have a speedo/tach cluster sitting in my garage. I got that cluster with the car.

The car has the oil/water/volt sweep gauges/bezel in the console atm. It is a 'stock' console, and I am assuming was the one from the factory. I was asking since it has the oil/water/volt sweep gauges in the car, and they were working,i should have the proper engine harness/main-harness/sub-harness'es to just change the speedo/clock cluster out for the tach/speedo cluster i have setting. I have the 'film' and the 'wiring plug'(to the tach) on the cluster i have setting(speedo/tach cluster).

I was asking if anyone had some info on how else to know, besides just ripping the dash open. I hate to just assume it will work, then spend the time removing the 37 year old plastic, to find out i chanced/did break parts of it, to be the wrong harness.

I'm tired of having two clocks. the tach would also be nice for logging launch rpm's. It's a bit more accurate than my ear. =\ Thanks guys.

 

While I have no specific experience with exactly the swap you are trying to make, everything I have read says that the harness installed in each car was specific to the gauge layout spec'd. In other words, they did not use universal harnesses that had all the connectors and wiring for all applications and just plugged in the ones needed. When swaps like this are done then you need to source a used harness for the setup you are installing if you want to keep it original. Or you can wire it per the link below. Hope this helps.

http://www.429mustangcougarinfo.50me...ew_page_11.htm

 

You cannot use the tach cluster unless you changeto a tachwiring harness. The main electrical plug that plugs into the back of the clock console will not plug into the back of a tach console.
At this point you havethree options:
1. Take the clock out of your current cluster and add the tach like I posted above.
2. Buy a tach wiring harness and replace switch it in.
3. Or you can find an accurate wiring schematic and swap the electrical leads in the plugs, and hopefully they'll come out in one piece.

 

Yeah, that's what I thought. So, here is the question. Where can i find either a schematic, so i can wire the car myself, or more preferably, a used good wiring harness? I should just need the one that goes from thecluster to the engine harness. I already have the working sweep gauges for oil/water/volts, and the sub-harness used for those. Anyone have a clue what I am going to be looking at for the harness cost?

Thanks for the helpful posts. James.

 

It sounds to me like you car originally had a tach/speedo combo. If this is the case, it shouldn't be hard at all to switch back.

 

That's what I thought, but why would someone swap out cluster gauges? If you are going thru the trouble to tear the dash open, why not just roll the #'s back on the odometer? =\. I'll just have to tear it open and see. I think I will just clip the 8 wires or so, you need to, to make it work.

 

This is not a simple plug and play swap. You're aren't going to simply unplug one cluster from the harness and plug the other one in. The plugs are completely different sizes.