1. what is the difference in 3.73 and 4.10 gears
2. and what is a "Tune"

 

3.73s are a waste of money, you want either 4.10s or 4.30s

its the ring and pinion in the rear end, the higher you go the faster your car will be, but they cause your car to turn higher RPMs, so lets say you have an 01-07 W/ the T-3650, stock gears you are at like 2400 at 80 mph (not sure just an estimate) with 4.30s you will run just under 3000 rpms

 

4:10's are lower than 3:73's & that means the gears turn faster. 4:10's have worse gas milage but go through the gears faster. if you travel alot like i do 3:73 is the way to go. if you don't travel, i would go with the 4:10's. a tuner reprograms your computer to provide more fuel and air. you can tune your car to run on performace for 87 octane or higher octain. the tuner will also reset your speedometer for the gear ratio change.

 

OH OK i get it thanks so much guys i really do appreciate it and i cant wait to get my first Mustang

 

3.73's for manual if you do hwy driving. A tune will help take full advantage of your mods and tire/wheel size/gear ratio. Definitely worth it. Superchips or Diablo make good tuners.....

 

OK STOP what year is your car? if you have a T-45 tranny, the OD ratio is .67, if its a T-3650 its .68, the 4R70 (auto) tranny is .70, so please, please tell me who came up with the auto 4.10s and manual 3.73s cause it makes ABSOLUTELY NO SENSE! and 4.10s will drop your milage a whoping 2 mpg on the highway, and my buddys around town milage acually went UP with 4.10s

so autos and T-45s go with 4.10s, the T-3650s should really go with 4.30s but 4.10s are fine as well

 

good posts^

but if you want to learn more about cars, try www.howstuffworks.com

i have read EVERY word about cars on that site

EXTREAMLY HELPFUL

 

A lot of people suggest the 4.10's in an auto tranny, especially on foxes, b/c the AOD sucks in stock form and needs all the help it can get. I've seen more people recommending 4.30's for it as well. And most people w/ 4.10's or 4.30's will get better around town gas mileage b/c the engine isn't working as hard to get going everytime.

 

yup and 4.10s on a t-45 = 4.30s on a t-3650

 

Your 1st gear ratio is also something to consider....T5 is 3.27 and so are some Tremec's (some are also 3.35). The T56 is 2.95 which won't be as likely to spin tires. I'm not sure about the T45, but I would imagine it's ~3.27.

Going w/ lower (numerically higher) rearend gears makes it harder to keep traction when launching/getting on it in 1st, so stickier tires would be very beneficial....otherwise it will just take some getting used to....

And don't worry about losing your top end....a friend of mine had 4.10's in his 95 cobra and could get to 120 easily and had room to spare.