Speedometer Driven Gear

1st Official Post

    Searched the forum but nothing came up. I recently installed a new cable and now the speedo works but is about 8 mph too high. Before I remove the gear again I would at least know what I am looking for. I have a '65 with a toploader and 3.50 rear gears. Should my driven gear be 17, 18, 19 or 20 teeth? I have stock tires. Thanks

    • Official Post
    Quote from recips

    Searched the forum but nothing came up. I recently installed a new cable and now the speedo works but is about 8 mph too high. Before I remove the gear again I would at least know what I am looking for. I have a '65 with a toploader and 3.50 rear gears. Should my driven gear be 17, 18, 19 or 20 teeth? I have stock tires. Thanks

    That combination takes a 17 tooth gear. Ford part number is C2DZ 17271 G. Keep in mind that the Mustang toploader uses a left hand helix gear compared to an automatic transmission. These are readily available and I have several NOS ones. The rule of thumb on number of teeth to make a change is one tooth for every 5-7 MPH. How many teeth does yours have currently?

    Also keep in mind that the HEH-T 65 Mustang Hipo transmission uses a different drive gear inside of the transmission than other standard Mustangs.

    -Fred-

    65 Koupe early San Jose Phoenician Yellow 4 speed
    66 GT Koupe Dearborn Blue 4 speed
    66 KGT San Jose fastback pony interior Silver Frost 4 speed
    64 Falcon sedan delivery 289 4 speed
    65 Ranchero 289 4 speed
    66 Corvette roadster 427/425 4 speed

    Fred, I didn't even pay attention to that when I put the new cable on. I just assumed that it was correct. I will take it out and check it in the next few days. as long as I don't have a 20T then I should be able to move up 1 tooth and get pretty close. Thanks for the info, you are always a great resource! -Eric

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