I swapped out my Sweep style speedo in my 1980 Malibu with idiot lights for the round gauge cluster from an 85 Monte. It took me the better part of the day. I bought the cluster here from a member. It started out blue so I took it all apart, paintetd it Camel to match, replaced all the bulbs with LED's, and changed the headlight switch bracket to a metal one from Mikes Montes. Then the hunt began for a bezel for my application as I have the switch in the dash and most of the ones I've come across weren't the right configuration. Finally scored one on Ebay it was claret but got painted as well.
In my search for the bezel I came across a housing that was trashed but it did have a 115mph speedo and a 6k tach with clock. SCORE! So I picked it up and took the speedo to get calibrated and cleaned and lubricated and reset to 000000. It cost as more to get it cleaned and lubricated and calibrated than the whole cluster. I had a harness pigtail from a car at the pick your part that fit the round style cluster so I was able to put it together and use my 12v power supply to test the lights and gauges for operation. The tach I actually wired up to the car using test leads to verify operation and checked it with my timing lights tach setting to verify. It was pretty close. I was going to change the column for a tilt but I'm still waiting for it to arrive and wanted to take advantage of the nice weather.
I scored a tach filter from a monte at the pick and pull. I cut the wire but not before pulling it out of the firewall with about 18 inches of wire before cutting. Using the tach lead from the scrap harness I was able to pigtail it in and make it fit in the new plug (white wire). I had to drill a hole in the firewall to push the wire through about a half inch in diameter to accept the grommet. I then spliced the wires under the dash and began to rewire the harness using the diagram from
maliburacing.com, it was dead on. I had a hard time with the speedo cable as the sweep speedo is in the center of the cluster and the round gauges has the speedo on the left. I opted to pull the speedo cable and re-route it so it came in on the left side. During the process, I had to repair the dash bracket that holds the wire harness as it was cracked. I used epoxy and reinforced it with some additional plastic.
All said, it took me the better part of the day to do the install and I still have to change out the sensors under the hood. It could have gone quicker if I didn't have to make the repair to the dash. I also had to pull and reset the cluster about 3 times as The wires on the harness were pushing out. I fixed it by bending the tab on the bottom side of the metal clip that goes into the harness bracket. I didn't get to use the headlights and get a night picture. I used white LEDs mixed in with a few blue ones as the blue was just too much blue. Now it has a blue tint and looks pretty good.
I purchased the white gauge overlays but that was prior to finding the stock 115mph speedo. I was also able to get the proper overdrive selector so it actually shows overdrive now on the indicator. We have one more day of nice weather so I may get to the sensors under the hood tomorrow. I also need to get the right drive/driven gears in the transmission to correct for speed. I also have to get all these spare parts (speedo, gauges, clock, and housing and circuit board as well as old cluster) ready to sell.