Correct Muncie Speedo Gear

[smittys69]

Anyone know the correct speedo gear to run in a M20 Muncie with the following information: 3:55 ration rear end and 17" wheels. Rear tires are 275/45/17. Thanks for your help.

Tim

[crash]

Tim, I have formula for speedo gears but I need tire Dia. and rear end ratio... Post back the dia. and I'll run the formula and get back to you...Crash

[smittys69]

According to 1010tires.com, the overall diameter of the rear tire would be 26.74". Again, rear end ratio is 3:55 / 1

[crash]

Tim, You need a large dia. 7 tooth drive gear on the main shaft, and a 19 tooth driven gear...Crash