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Hey, i was already to order my 3.90 gears to have them installed, and i called a guy that works for ford and he is doing them for 175 since i can tune my speedo for new gears with my predator. I asked my g/fs dad since they own a salvage yard and they know lots of mechanics and stuff and he asked a guy who said he would do it for 240 but he said that i would have to be insane to put htat high of gears in my car. he said that my car wont last anything if i drive it on highway, and my gas milage will blow, and that the highest he usually puts in is 3.55 and pushing 3.73s.

Now i know that gears will raise RPMs but i have heard with 3.90s for my 02 GT in 5th gear around 75mph is 2600rpm and about 2000 at 50 in 5th. i know that gas wont be best on high speeds but i have heard that on low speeds helps out because engine wont bog down as much....

should i go with 3.73s or 3.90s, i drive my car daily.

let me know
thanks
 

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carguy1985 said:
Hey, i was already to order my 3.90 gears to have them installed, and i called a guy that works for ford and he is doing them for 175 since i can tune my speedo for new gears with my predator. I asked my g/fs dad since they own a salvage yard and they know lots of mechanics and stuff and he asked a guy who said he would do it for 240 but he said that i would have to be insane to put htat high of gears in my car. he said that my car wont last anything if i drive it on highway, and my gas milage will blow, and that the highest he usually puts in is 3.55 and pushing 3.73s.

Now i know that gears will raise RPMs but i have heard with 3.90s for my 02 GT in 5th gear around 75mph is 2600rpm and about 2000 at 50 in 5th. i know that gas wont be best on high speeds but i have heard that on low speeds helps out because engine wont bog down as much....

should i go with 3.73s or 3.90s, i drive my car daily.

let me know
thanks
That guy said you would be crazy to put in 3.90`s, but maybe he really dont know Mustang`s that well , it`s not like it`s some 82 Monte Carlo with 135 hp
 

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Discussion Starter #3
i really want the 390 should i got with 373s now though?
 

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either way, your gas mileage will suffer....bnt really, what did u expect.....u are installing performance parts and either u can go fast and eat more gas, or u can remain stock.....the higher the gear, the lower your top speed and the quicker your accelaration....with my auto tranny, i have a set of 3.73 gears waiting for install....this is only cuz i drive a lot of highway miles....i would have selected 3.90's....with 5 speeds, i would go 3.90 unless u plan on adding a supercharger in the future....
 

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I recently put 4:10's in mine. Gas mileage if i baby it is 18-19 if i hammer on it all the time it's 16-17. Highway was 25-26 at 70 mph it was at about 2400 rpm. So far it's been the best upgrade that i have made. With the fluid and all i paid $300 to have mine installed. Well worth it. I drive mine daily and have seen no adverse effects.

 

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Discussion Starter #7
Hey silver03GT i sent you a Private Message.
 
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