Gear choices need help

Old March 7th, 2019, 04:23 PM
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Gear choices need help

Hi Guys,

I need some expert advice on what gears I should use. I have a 3 speed 1971 cutlass convertible with a posi rearend running 3.08 gears. I have cooper cobra GT tires 225/70R14. Here are my questions.
1. I'm switching from a 3 speed to a 4 speed with a hurst pro comp shifter..... should I get a Muncie or Saginaw?
2. should I stay with the 3.08's or get something else? what should I consider? I would like to be able to burn tires but I don't want to be screaming going 65mph down the highway. thanks in advance for the replies and please let me know if I need to provide more info. thanks.
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Old March 7th, 2019, 07:30 PM
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Monzaz would be the one to reach out to on this board for gear advice but I'd surmise you could go up to a 3.23 gear set with the 4 speed and you'd likely be close in rpms at highway speed to what the 3.08s turn with your 3-speed, but with noticeably improved acceleration grunt from off-idle.
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Old March 7th, 2019, 07:48 PM
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A thought....... a wide ratio Muncie (low first gear) and keep the 3.08's. You can always change rear gears later. You'll have the same RPM's at highway speed that you have now.
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Old March 8th, 2019, 06:21 AM
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The Saginaw trans was only used behind low-output engines. You want the Muncie, wide ratio. An even better choice is a Super T10 with the 2.88 first gear. If you can find one of those (used in late-70s GM cars), I'd keep the 3.08s. If you go with a Muncie with the 2.52 first gear, I'd go 3.23s. Obviously, any four speed will have a 1:1 fourth - unless you can find one of the overdrive A833 transmissions used in the 1980s Chevy trucks. These are Chrysler four speeds but third was swapped to an OD ratio, and the shifter is changed to go 1 - 2 - 4 - 3, so it's really a wide ratio three speed with an OD gear. Be aware that the A833 requires bellhousing mods to be used on an Olds.
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