Looking for a gear between 3.73 and 4.10s for my '03 GT. I read someone had hem but do not recall where. Does anyone know if they are available and where they can be purchased?
Thanks!
Thanks!
3.90s - Do they exist?
- Thread starter apk1971
- Start date
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Dark Knight GT
I can't get it up......ok that didn't sound right.
I believe Pro5.0 gear and Motive Gear both make 3.90's. Not aware of where to buy them though. Might want to do an internet search for Motive Gear and Pro5.0 gear.
SonicBlueBabe
New Member
I got mine from Pro5.0 Great choice BTW!!!!! I was also deciding between the 3.73's and 4.10's, and I saw these. They are perfect, I love them! 
decoy562
New Member
Thank you for the direction...
1 other question, since this is not a ratio not offered by ford, will I have problems finding a speedo calibrator to compensate for the 3.90 gears?
1 other question, since this is not a ratio not offered by ford, will I have problems finding a speedo calibrator to compensate for the 3.90 gears?
They do exist and your on the same boat i was in. i was looking for the same thing and did allot of research here. This is what i came up with. I’m sure somebody will correct me if I’m wrong.
Ford Racing gears are the best. They don’t offer 3.90 why i have no clue.
Motive and any other gear making company seems to use softer metals. This is a controversy subject. Seems like a good chunk of people seem to think that way and others fight the argument.
People with 3.90 seem to be happy but some do complain about rear end noise. i strongly believe that the 3.90 is a happy medium between 3.73 and 4.10. With a good pro mustang mechanic shop and not your local general mechanic shop will make a world of difference when it comes to keeping the gears quit and running good. After all your torque goes thru them.
I’ve also come to a conclusion that if you think ahead about what is your ultimate goal that you will only do things once. Especially since mechanic rates for a good pro shop are not cheep.
If you plan to go with charger like vortech, procharger, paxton or any turbo. that you’ll be fine up to 3.90 for highway use. They might be a little high on rpms depending at what speed you like to drive in the highways.
If you decide on a kenne bell personally by far the best or a Eaton you will have to cut back on the 3.90 and go with 3.55 or 3.73. Because the twin screws seem to kick in hard from idle to redline and usually more expensive than the others.
This is another controversy subject and i don’t mean to piss anybody off with any of these great power adders. Again im not speaking from experience just from what I have read.
Good luck I hope this helped.
Ford Racing gears are the best. They don’t offer 3.90 why i have no clue.
Motive and any other gear making company seems to use softer metals. This is a controversy subject. Seems like a good chunk of people seem to think that way and others fight the argument.
People with 3.90 seem to be happy but some do complain about rear end noise. i strongly believe that the 3.90 is a happy medium between 3.73 and 4.10. With a good pro mustang mechanic shop and not your local general mechanic shop will make a world of difference when it comes to keeping the gears quit and running good. After all your torque goes thru them.
I’ve also come to a conclusion that if you think ahead about what is your ultimate goal that you will only do things once. Especially since mechanic rates for a good pro shop are not cheep.
If you plan to go with charger like vortech, procharger, paxton or any turbo. that you’ll be fine up to 3.90 for highway use. They might be a little high on rpms depending at what speed you like to drive in the highways.
If you decide on a kenne bell personally by far the best or a Eaton you will have to cut back on the 3.90 and go with 3.55 or 3.73. Because the twin screws seem to kick in hard from idle to redline and usually more expensive than the others.
This is another controversy subject and i don’t mean to piss anybody off with any of these great power adders. Again im not speaking from experience just from what I have read.
Good luck I hope this helped.
MineralG2k2GT
New Member
Turbo92PGT
Member
I'm trying to find out what gearing I should put in my car. I'll probably just get some 3.73's because I have heard great things about Ford Racing gears. I'm going to be running some kind of nitrous kit on my car in the future, so I dont want to just spin the **** out of the tires. So 4.10's maybe arent a good choice for me, I really dont know though. Not very experienced with it
