Re: 1989 IROC-Z Tac Problem
You probably don't want a 700R4 kicking into first at 20. It would hit redline pretty quickly (depending on your rear gearing). As for the tach, I'd try cleaning/reseating the connectors on the distributor. If that doesn't work I'd pull the cluster and reseat the tach. The contacts are pretty flimsy clips in 3rd gens. Do the other instruments while you're in there.