I was wondering if there was any way to swap my 85 firebird 2.8l gauge cluster with 85 mph cable powered speedometer and fuel gauge (no oil pressure or tachometer or temp gauge) with a cluster from a 87-91 trans am. My main concern is I don't know how the tachometer or speedometer would hook up. Any info would be nice I would prefer not to use an after market tachometer but if there are some good ones out there that go above 85 mph and are comparable with the cable speedometer that's fine also.

 

It won't.

The later models used an electronic speedo, not cable.

It's possible that there might be some pulse generator kind of thing that might interface them but it's certainly not a direct hookup.

It was not legal to sell to the public a car with a speedo that indicated higher than 85, from about 73 or so up to 85 (the 86 model year actually). AFAIK all Firebirds with V8 85 up had electronic speedo. So I'm afraid you're largely out of luck.

 

crap, I'd love to have my car just with some mods like this but it looks like I'll have to tough it out and buy a 87-89 trans am. I want a gta but they didn't come in manual, so I'm liberally screwed

 

Back in the early 1990s I had a 1987 Trans Am that was a 305 4 barrel CCC that had a cable driven speedometer . It had a cable running from the transmission to a strange little unit that was the pulse generator , and then a second cable that ran from that unit to the speedometer . The reason I remember the little unit thing so well was that it began binding and making the speedometer jump , and it was kinda expensive to replace . I had considered getting rid of it with a cable straight from the transmission to the speedometer , thinking it was only for the cruise control (which I never use anyway) but my GM mentor at the time told me the TCC wouldn't engage without it , so I ponied up the $$$ for a replacement

 

Maybe only the EFI ones were electronic starting in 85. A firebird specialist would know better than me.

GTAs DID come in manual. In fact one of the coolest ones I've seen was a 89 with G92; so it had the better T-5, the 3.45 9-bolt, and PBR brakes.

 

Up to 1985 the Firebird used a cable driven speedo. Starting in 1986, the better clusters used an electronic speedometer. Base model Firebirds with the basic speedometer/fuel gauge & idiot lights clusters were still cable driven.

There are threads on converting from the Firebird mechanical cluster to the electronic cluster, but really if you're dealing with a V6 the easy solution if you plan any mods like a V8 swap, is to dump it and get a V8 thirdgen. Or a V8 parts car. Changing the cluster is a pain in the rump, changing the V6 to a V8 means changing pretty much everything under the entire car.

Early thirdgens used a cable driven transducer to turn the spinning cable signal into an electronic signal the computer and cruise control can read. It's an archaic system that only sorta worked in the early 80's by early 80's standards. Later cars used a signal generator on the back of the gauge cluster, and eventually everything ended up with a VSS in the transmission tailshaft.

All that's little more than useless trivia. If the car is a V6, don't spend any money modding it, you'll never get your money back out of it.

 

If you want a quick and halfways cheap way of getting a 145mph speedo, grab one from a camaro that is cable driven and make it fit. It doesn't take too much work and looks good if you cover the high beam with black filler material and paint a white line on it. I did that mod before i went to electronic speedo and was very pleased how it turned out.