I just wanted to put in my 2 cents.First of all to each his own.I know the first post in this thread is like two years old but i think people didn't realize he had a 97 cobra.Why would anyone suggest putting 3.55's or 3.73's in.That would be like suggesting 3.08's or 3.27's for a fox body(5 liter).I have a 98 cobra with 4.30's and they are perfect.Before anybody spends their money on gears make sure you do your homework so that you wont have to change them again just because the gears wasn't enough.
Or you can be like me and 3.73's is too much gear for what I am doing.
I have an 89 LX with a 5.0 and manual transmission. With the stock gears of 2.73, I would get about 24 to 25 mpg Hwy and 17 to 18 City. I switched to the 3.73 and things changed significantly in the mileage area Hwy best is 18 mpg and City is in the 11mpg area. The 3.73s made a huge difference in the acceleration area almost making first gear pointless; you were changing out of it in less than 2 seconds (very similar to my stock 2000 GT). You can take off in 2nd Gear without using the clutch too much (unlike the 2000 which does not have the torque that the 5.0 has). With the free flow exhaust system the higher revving engine did make significantly more noise at cruising speed with the engine running more in the 3K range than the previous stock 2K. Which is best? I love the acceleration, do not like getting stuck in traffic and having such a short 1st, mileage hurts the pocketbook at $2+ per gallon, noise is sweet on the street (turns heads) a little annoying on longer trips. My advice is to get to know fellow Stangers in the hood they will take you out in their car you can sample their setup and you can determine what is best for you. I would now opt for the 3.55s just to try and hit a more middle of the road between the two setups. Be true to yourself you know what kind of driving you do if the strip is not a regular thing than stay with the lower gears however if the Ό mile is where you are at, then 3.73s are better and 4+ are for the more serious. Dont forget to change your speedo gear otherwise if the wife drives the car and gets pulled over you will never hear the end of it!
the car is automatic, and i dont really ever race it at a track or anything, just on the street. not hardcore racing or anything like that, jsut goofing around.
i do drive highway every now and then, but mostly it is used in daily driving, outside of winter.
and if it helps any, i actually would never be going more thatn 100 in my car.
i just want a better jump off the line and down the stretch.
some people i talked to said that higher gears would make my car top out at 85 mph on the highway. i dont think they knew what they were talking about though.
I HAVE 4 10S AND I THINK ITS JUST TOO MUCH.373 IS BESTFOR AUTO the 410s are redicoulous if u love to spin the tires and chiprps,and waste alot of gas its ok.the 373 is little diff from 410 in 1/4mile times,but a reasonable diffference from 355, BOTTOM LINE AUTO=373 UNLESS OVER 250RWHP OR ABOVE,,,IF SO THEN 355
STICK IS REALLY 355 TURF OR LOWER IF U HAVE HP,,THATS MY OPINION
MY AUTO ALSO HAS SHIFT KIT AND 2600STALL...MAKES ALL THE DIFFERENCE IN THE WORLD.WAYYYY MORE NECK SNAPPING TIRE CHIPRPING FUN
like every other serious forum this one is very opinion oriented.
But its close 3.55's and 3.73's are seeming to get the same amount of representing.
But it seems that manual daily drivers/with mild racing habits should go for 3.55's
manual d/d with a lot of racing habits should go with 3.73's
both the 3.55/3.73 arent gas friendly so its up to your habits ,1-3mpg is a lot, but like i said pleasing our habits has a lot of importance also...
Personally i would get 3.55's, cause along with other mods; cam,headers,intake,exhaust,and a lil spray. Its perfect for a d/d street machine driver who doesnt mind losing to the big dawgs, as long as he can take advantage of he lil kids( Im sorry but I hate rice)
and for gearing in autos, well they suck so much they should be putting in like 5.XX's
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im surre no one cares about this forumn no more, but i was reading and calculating and found about a 3oo rpm difference in 3.73's vs. 3.55's; so with 3.73's your burning 300rpms more, but with 3.55's your saving that 300 and also 300 rpms behind in the star out gears....
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Well I'm running 3.73's and though I haven't tried another I like this setup. First is short especially if you've got it wide open. Has good pull but can't comment on gas milage yet. So far I'm getting about 6 mpg. Still new to me so I'm looking for the culprit. Rebuilt the carb and it got better but think their may be a hidden vacuum leak. Still runs good though. However I do have a gripe about the cruise like the guy shortly before me. At cruising speeds the noise with my exhaust can be annoying. 55-60 mph is in that "perfect" rpm range where the exhaust is really loudest. So can be annoying unless you need incentive to speed. BTW that RPM range is 2000-2200.
It will burn in first. I can spin one in second until shift. Third grabs and goes as fast as I want to go. 4th well I don't usually leave my foot in it that long but it went past 85(as far as the spedo registers) and engine topped out after 4000. It did accelerate but you could litterally feel it loose power. I don't use 5th except to cruise :P
Found out the hard way that you could take off in second pretty easily with 3.73's too. Shifted to second and the gear shift kept going and going lol :P needless to say I was glad I was close to work where I could get tools. Had to drive through town using only second :P
i have a set of 3.73 s on my pony but its an auto. i felt the difference from the stock gears. before i purchased my pony i had an 87 5.0 stick with 3.73 s and i use to spin my tires in 1st and in 2nd. i also have the same problem, my speedometer is of by like 8 - 10 mph. i would go with 3.73 s.
alright so if 3.73 seems to be the gear for aod equiped auto 5.0, what about an aode equiped gt like my 95? i have been thinking 4.10, this along with heads and intake manifolds will be one of my first real mods.
i'm not tooo worried about milage, i just don't want to be cruzing the highway at 80 mph at 3,500 rpm. can someone tell me my rpm per mph with these gears? thanx
I'll throw in a couple technical questions to go along here.
Ford 8.8 3.73 and 3.55 gears sets - are they hunting or non-hunting ratios? Why do I ask? Determining this partially dictates how they are set up. Non-hunting and partially non-hunting are supposed to have "timing" marks on them. If you don't get them lined up they will wear quicker and will be noisier. I don't see any timing marks on the 3.73 and 3.55 I have but that may just be because the paint marks are worn off...
Second, these are used Ford gears. I bought them that way on purpose. They look like new condition and from what I've read from a couple sources they should be quieter than new.
Being that they are used, the pinion bearing is installed. It looks fine with no wear. I've had a couple technical people tell me I can leave the original race in the carrier and just put the pinion in with the current bearing - manufacturing tollerances are close enough today that they will match. Also, I've been told that Ford has tight manufacturing tolerances and if I keep track of the shims, I should be able to change gears without the need for a "high tech" setup - pinion depth will be good so all I will have to do is check backlash.
Anybody ever had any experience installing used gears?
