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Discussion Starter · #1 ·
I just picked up a Tremec Tko 500 to install in my 64 Falcon. It has a 3.27 first gear ratio with .68 5th. Any suggestions on a rear gear ratio, assuming a 25-26" diameter rear tire, and a basically stock 302? Plans for the car is a driver, not a race car. Any thoughts?

Nathan
 

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Given your RPM range for cruise, I would mimic the factory setups for all-around performance with decent mileage. That would be a rear gear around 3.25:1, yielding about 1400 RPM at 50 MPH, and about 2000 at 70 MPH. Alternatively, a 3.00 or 3.55 gear would be about as far as I'd go for a DD and stock 302.

With the low 1st gear, it would have the equivalent first gear torque of a close-ratio Toploader 4-speed and a 4.58:1 gear, or wide-ratio Toploader with a 3.82 gear, but also 1000 RPM less at 70 MPH.

Values calculated with a 225/60-15 tire at 26" diameter.

David
 

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Discussion Starter · #3 ·
Thanks David, I ran 3.50 gears through calculator and I figured that was about as low a gear that I would want. Your thoughts help to confirm that. My car currently has 4.11s which would pretty much render a 3.27 first gear useless I would think.

Nathan
 

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Almost. You can't even punch it and get across the intersection in 1st gear - if you have traction. I found with deeper gears at 3.50 and lower, I will hardly use 1st gear on the street, and always start in 2nd in normal driving. That kind-of kills the point of a 5-speed, giving you a 3-speed plus OD. If you needed the 4.11s for the track, then the OD helps, but otherwise you're limited.

David
 

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The 3.27/3.31 Ford used in the recent Mustangs works very well. My TR3650 w/ a 3.38 1st and stock wheels/tires worked well w/ 3.27s but with my 3.73s, I find that I use 1st like a creeper/granny gear now. That and with the .62 OD, it's a touch too high for me for highway use.
 
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