So I bought an 85 IROC which came with fuel injection and I'm guessing a non 140mph speedo? None of the factory gauges work except for the gas gauge which is everywhere Nd the speedo is off by like 30 mph or something. The aftermArket gauges work though. My car has a 305 out of an 89 firebird and it has a 4 barrel carb on it. The previous owner said it has a 700r4 tranny but originally had a t-5. Car runs awesome but I need gauges