I'm new to the Camaro scene. My son purchased an '84 Z 28, and it seems pretty cobbled up. I'm sure the car was originally a 305. It now has a 355, carbed, HEI, 700 tranny, w/an IROC rearend (discs). Here's a couple of problems that I'm working on. It has an 85 mph speedo. (all annalogue) To go 55mph the guage has to read 68. The tach registers way more rpm than it needs to. i.e. 1500 rpm could read 9000. The oil pressure and water temp guages are disconnected somewhere as after market guages were installed. We'd like to back to stock guages in the cluster. Would an instument cluster change solve this? If so what year/model do I look for?

Welcome to TGO.

The rear end swap may have caused the speedo to read incorrectly. You'd need to determne what the gear ratio is, then install the correct trans drive and/or driven gears. Considering the gauges are after market, I'd guess that a simple cluster swap won't be the answer. If the tach itself is bad, however, you could replace it (replacement is a pull out, plug in affair that won't take ten minutes).

JamesC

The stock gauges are known to be inaccurate so if the aftermarket ones are done tastefully I might think about keeping them. The tach sounds like it may be from a V6 if it's off by as much as you're saying. The eighth VIN digit should be either a G or an H. If you're able to remove the cluster, there should be two long electrical connectors. If these are intact you should be able to plug a different one in. You can also look into upgrading to a 110 or 140 speedo or whatever individual gauges you may need. The speedo has a tab that locks the cable in place.

This link shows the long connectors on a Firebird cluster and the connectors are similar to a Camaro's but in different locations. You can also see how the gauges are attached.
Link (Instrument Cluster circuit board???)

Image of the speedo clip.


The White Book (Camaro reference) says the '84 Z28 used the double pointed speedo so if this was true the cluster was possibly swapped with a V6 cluster causing the tach issue. The double pointed speedo was never really popular.

If you can post a picture we might be able to help figure out how extensive the changes were.

Thanks, I'll work on changing the speedo gear first. I'll try finding a used tach or a different cluster w/ 145 mph speedo. I'm sure that I'll find that most of the wires were gutted when the previous owner went aftermarket.

The 8th digit is an H. It's quite possible that the cluster is from a V6. It will be this weekend before I can work on the car again. I'll see if I can get a couple of pics then.

Tire size can throw speedo off to may be combo of both. Just a thought.

You may just need new speed gears in the transmission.
I know I need to replace the ones in mine.
I am however to stupid to determine the gears I need.
I will eventually slow down long enough to learn or ask my daugher the math whiz to do it for me.