I have an 87 firebird with a mechanical speedo 2 gauge cluster and been thinking about changing over to the 4 gauge cluster. I'm going to try to find a mechanical speedo 4 gauge cluster. I'll use electronic if I have to since my t5 I'm swapping in is electronic I can do that just not super familiar with switching to an electric cluster. I was mainly wanting to know how hard it is to hook up the tachometer the temp, oil pressure and voltage gauge or if there is a write up I could get a link to that would be appreciated.

 

First,..... I do not know how a 82-85 cluster will work in an 86+ Firebird. The Camaro cluster wiring changed in 86 and it's possible that the Firebird cluster wiring changed at the same time too since that's when the electric speedo sending unit was introduced.

I converted my step-dads 86 Firebird "BASE" ( cable speedo) cluster to the 86+ "Gauges" ( electric speedo) cluster a while back. IIRC the wiring for the electric VSS was already in place but not used when the non-gauges cluster was factory installed. Also pretty sure that the GAGUES cluster itself plugged right in. His car was a V6 converted to a V8 so I had to install gauge type sending units ( Oil, Volts, Temp ) on the engine and had to install an electric speedo VSS in the tranny as well as a yellow Speed Buffer Assembly. I used a Camaro engine bay wiring harness so the tranny electric speed sending unit wiring wasn't there and I had to add that too.






If this was my project,...... I'd pull the passenger side trim panel from the dash and check to see if the VSS Buffer Assembly plugs are hanging back there un-used. They *might* be taped to the harness and kinda' out-of-site at first glance, so look close if you don't see it right away ! I'd also look around at the back of the engine for any wiring that might be tapped up to the main harness; in 87 the Firebird tranny speed sensor wiring ( Yellow and Purple wires ) passes thru the C100 firewall connector & usually lead from about the center of the engine bay wiring harness and then drops under the car to the tranny. I'm GUESSING that if the VSS Buffer plugs are there - the VSS wiring/plug would be there too. If there's no Speed Sensor wiring in the engine bay, you should be able to splice into it under the dash & run the 2 wires thru the firewall, then lead them to the tranny VSS. Here is the 87 Firebird C100 ( dash-to-engine harness ) connector schematic: ( VSS = 'D4' and 'E4' )


FYI The firebird used 2 different electric speedo sending units in the tranny. The first type was used from 86-89 Firebird and the second type was used in the 90-92 Firebird and Camaro. I've always used the one that matched the car/wiring based on the car I was building. I don't think ( just don't KNOW) if the 2 types are compatible or not so just be sure that you buy/get/use the proper electric speed sending unit if you go electric !

Good luck !