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4.56 Gears with a TH400

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Old Feb 12, 2008 | 11:04 AM
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lilblackZ28's Avatar
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Default 4.56 Gears with a TH400

Are 4.56 gears to much for a th400 with a SBC 350...I am going to drive the car daily and race it a few times a year.They are the gears that came in the car I was thinking of going to a 3.73 or a 3.42.What do you guys think.
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Old Feb 12, 2008 | 11:12 AM
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Thats going to be a awfully expensive commute, I would run a calculator, Also there isnt a lock up option for the TH400, so its going to spin higher and slip which will have the motor revving additional rpms.

I personally would run no more then 4.10.

With that gear if revving out to 7k wll allow approx 126mph max speed. But if you have a GEN I SBC, I dont know what you plan on revving out too.

Based on the limited info, its going to be too much.

I had a TH350 w/ 3.08 gears in my Chevelle and it would run around 3k @ 75 w/ a stockish style stall.

That my exp.
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Old Feb 12, 2008 | 11:16 AM
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3.08 gear here with TH400....70MPH is around 3K with a 3200 stall.
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Old Feb 12, 2008 | 12:23 PM
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Its in a 74 nova SS the kid was setting the car up to drag race it.I didnt if those would be good for 1/4 mile b/c its not tubbed it just has the orignal wheels on it..I am looking to run low 13s maybe high 12s..what do you think would be the best gearing for the car. Its got a 2500 stall.I am going to put little taller and wider tires on the rear if they makes a difference.
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Old Feb 12, 2008 | 12:50 PM
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Mid 3.XX gear should be more then sufficent, its driven on the street more then its raced.
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Old Feb 12, 2008 | 12:55 PM
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So do you think it should 3.42. or 3.23..its going to be highway some fo the time...I know its not going to get great gas milage but I would like it to be decent..But still beable to get the job done at the track.
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Old Feb 12, 2008 | 04:26 PM
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3.42's with 26" tire is fine for the highway with the TH400,i just swapped out to 3.73's and 28" tires.
BTLFEDSS
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