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Discussion Starter #1
Want 3.90 gears for my 08. I usually use Ford Racing but they don’t offer 3.90’s. Can anyone recommend a manufacturer? I can only find stock replacement gears but I’m looking for the best quality for obvious reasons. Thanks
 

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2014 GT500 Coupe SGM " 1 of 1 "
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The " best " gears are Ford, your choice is 3.73 or 4.10, do you want 3.90's bad enough to live with " good enough " ??
 

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If you feel like wheel or tire shopping a taller tire can knock down your rear gear ratio. My '08 was lowered but I was still able to run a taller 28.7" MT 305x45x18. With the extra OD tire the Ford 4.10's were closer to 3.85-3.90 rear gear.. The 305's called for 10-12" rims but at the time I had also purchased 10" wide American Muscle wheels. The 305's looked stuffed in the rear wheel well ( actually about 3/4" to the fender) but they never rubbed or made contact with any part of my car.
 

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2012 SVTPP with a heavy dose of 2013 components
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Motive Gear and Eaton both make a 3.90 gear sets. I'd stick with one of those.
 

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Discussion Starter #5
Thanks for the feedback all!

3.90’s were my compromise with myself since I would really like to go with 4.10’s. The math works out to 35-38 mph in first which is short but not crazy short. The problem is I would really need either a 13-14 trans or to have my 6th changed to the taller gear both of which are cost prohibitive right now. I’m doing some upgrades to my sons truck while he is in basic training and that box of new FR 4.10’s is just sitting there and he won’t be home til Christmas.... but I had to be realistic about the highway down side. There is a 4 wheel drive shop I have used for years for rear end work and I thought I might save a few bucks if I brought him both vehicles so that is why I was looking for the 3.90’s.
interestingly I found this while I was looking for gears


so we’ll see what I can work out. I’ll update when/if I get it all done. Cheers!
 

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My buddy makes 775FWHP on his '07. He switched to 410's....STILL with stock wheels and his older MT's were actually smaller than stock so he's closer to 419rear gear....according to a website calculator. He did it because in our are he felt nobody runs from the dead. Now...from a roll he can play hard from 20mph in 2nd gear.....rolls hard from 50-60+ and loves the fact he discovered he actually had a 6th gear. So yeah........you do give up running hard anywhere with guys in 1st. His only comment was he should've done this gear mod from 373 to 410 years ago. Sometimes there's a trade off and it all depends on how you want to drive.
 

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To me running 4.10 on these cars is a waste. To each is own but with the high hp these cars make it really isn't needed like it was years ago. I have 3.73 and I even think that's too much at times. Maybe I'm not a good driver but I like a somewhat usable first gear. It's kind of pointless to have a 900hp car and get beaten off the line by cars with less than half of the hp you have

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