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Old 09-17-2024, 07:23 AM   #1
Palf70Step
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Re: Rear gear Ratio Opinions/Suggestions

My 70 was changed to 3.08, makes big difference on the highway.
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Old 09-17-2024, 11:12 PM   #2
slikside
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Re: Rear gear Ratio Opinions/Suggestions

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Originally Posted by Palf70Step View Post
My 70 was changed to 3.08, makes big difference on the highway.
Do you have a 350 motor and a tach?

Just curious what your rpm is on the highway. I"ve never bothered trying to connect my clunky bench tach (for tuning) for a test drive...
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Old 09-18-2024, 07:10 AM   #3
Palf70Step
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Re: Rear gear Ratio Opinions/Suggestions

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Do you have a 350 motor and a tach?

Just curious what your rpm is on the highway. I"ve never bothered trying to connect my clunky bench tach (for tuning) for a test drive...
350 yes, Tach yes, 3 speed manual, so at highway it would be sam as T350. Rpms are about 2300 at 70MPH, 60 is a hair over 2K. 265/70x16 tires or about 30.5 in high
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Old 09-18-2024, 09:35 AM   #4
MikeB
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Re: Rear gear Ratio Opinions/Suggestions

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Originally Posted by Palf70Step View Post
350 yes, Tach yes, 3 speed manual, so at highway it would be same as T350. Rpms are about 2300 at 70MPH, 60 is a hair over 2K. 265/70x16 tires or about 30.5 in high
A TH350 would have a little slip at highway speeds, depending on load. My old tach wouldn't fit after I shortened my column, but I remember there was a 200-300 PRM difference between a slight downslope (light throttle) and an upslope. So with 29" tires, let's say if you see 2100 on level ground to downslope, that would be 2300-2400 so on an upslope. Of course the amount of "slip" depends on the converter.
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Old 09-18-2024, 06:43 PM   #5
slikside
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Re: Rear gear Ratio Opinions/Suggestions

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Originally Posted by Palf70Step View Post
350 yes, Tach yes, 3 speed manual, so at highway it would be sam as T350. Rpms are about 2300 at 70MPH, 60 is a hair over 2K. 265/70x16 tires or about 30.5 in high
Yeah, mine came out similar on Geezer’s calculator. I have 30” tires.
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