Just bought 91 Z-28 with 5.7, Only thing wrong with it is that the speedometer doesn't work at all. All other gauges function properly. In my quest of checking voltages, cleaning connections, etc... I found that there is a place for a small circuit card right below the speedo; that card is missing, just an empty space and dangling 4-5 wire connector. I've searched the web, rooted through my local salvage yards and called a few thirdgen specialty stores, no luck. Guy on the phone did mention that the 110mph card should work with my 140mph speedo but wasn't 100%.

If anyone can provide me with a part number, schematic, place to buy, or any information at all, it would be greatly appreciated.