You’ve got questions, we’ve got answers. We work with the Summit Racing tech department to help you tackle your auto-related conundrums. In this week’s Mailbag, we’re discussing mating an electric speedometer to a cable-driven Turbo 350 transmission.
Q: I have a Chevy pickup truck with a 350 engine, a Turbo 350 transmission, a 9-inch ford rear axle with 3.50 gear, a limited-slip differential, and Mickey Thompson 31-18.5 rear tires.
My problem is with the speedometer. It works with an electric sender and I have the old style Turbo 350 that uses a cable-driven speedometer. How can I get the electric speedo to work with the transmission?
A: There are aftermarket electric speedometer sending units that screw into the transmission where the cable would normally go. VDO makes a good one. You might need to change the speedometer gear for the transmission to correct the speedometer reading. You should be able to get that gear at a local GM dealer.
I guess it’s cool that you can even do this, but I don’t know why you’d want an electric speedometer over an analog one. But I know, I’m probably old fashioned for saying that.