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TH400 and gears for the street/highway

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Old 08-11-2010, 07:05 PM   #1
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Default TH400 and gears for the street/highway

I wanted to get a general idea of what gear are being ran with street/strip application and TH400s. This is for a boosted car, so I'm looking for a good cruising/racing gear.

thx in advance
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Old 08-11-2010, 09:37 PM   #2
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3:73 is a good gear for highway and strip thats what I have in my car. I have a buddy with twin turbos and he has the same gear running a 28inch tire.
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Old 08-11-2010, 10:51 PM   #3
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3.73's aren't too good for the highway at all. They work great for the 1/4 mile but not on the highway. At least that is how it is with 27" inch tires that I have. I would think that 3.54's or even 3.08's might be better.
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Old 08-12-2010, 04:30 PM   #4
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I would not go with a gear ratio higher than 3.23, 3.08 is a good gear ratio for highway driving with a TH400, depending on what your tire height is.
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Old 08-12-2010, 05:17 PM   #5
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I've been running 4.11s with my TH350 and 27" tires for over two years now.
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Old 08-12-2010, 05:20 PM   #6
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I vote 3.73's

Any transmission without overdrive isn't good for MPG anyway, so you might as well throw that out.
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Old 08-12-2010, 07:14 PM   #7
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My car is a 11.3:1 346, PRC heads, MS3 and has a 750 carb and it only used 3 gallon of gas on a 50 mile trip. I figured it would have been worse but I was shocked when I put gas in it before I headed home
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Old 08-12-2010, 07:47 PM   #8
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I drove a 42 mile round trip with my TH400 and 4.33's and used about an 1/8th of a tank, wasn't too bad considering..
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Old 08-12-2010, 08:31 PM   #9
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if its boosed i would post in the fi section
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Old 08-13-2010, 08:24 AM   #10
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id go with a 3.50 or below you want some load on those turbos
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Old 08-15-2010, 11:42 PM   #11
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I run 3.00 gears in my moser 9" with a 88mm turbo no issues at all with a TH400
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Old 08-16-2010, 06:01 PM   #12
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I'm using 3.46's with 26" tires. I want some 3.07's though. $600 for dang GTO gears though...
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2005, 307, 373, 400, acheter, driving, gardena, gear, gears, good, gto, highway, pontiac, ratio, street, th400

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