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I am realley seriously trying hard to decide what rear end ratio to upgrade to in my 84 auto. ive owned the car for a little over a month now, and I dont know much about its past, it has some upgrades already done, like the k&n filter, trans shift kit, and new top end of the motor with a mild torque cam, but I believe my tq. converter is stock. ( I think ? ) what do you think stall speed is on a stock converter 1k or 1.5k?

how do I go about determining what gear ratio is in my car now?
im guessing at some crappy 2.?? ratio now, so its either the 3.07 or the 3.73 are the ones I keep hearing about, but it seems like the 3.73 will take its toll on a daily driver, that hardly ever goes to the drags. then again every time I get first at a redlight its 0 to the speed limit :laughing: as fast as she will get there.

are there any other gear sets out there that fall in between the 3.07 and the 3.73 ? - maby something like that would be better for my driving habits?

or should I be looking for a mild stall (2k) tq. converter and then go with the 3.07 gear set to acheve what im looking for?

im not realley trying to break the bank doing this upgrade, the rear end needs to be strong but not bullet proof, im using the crossfire inj. and im shure there is a reasonable hp limit those things can make when their maxed out. should I look in to buying some one elses rear end housing with gears already in there? or will buying the gear set and a install kit be cheaper after having the gear mesh set correctly by someone who knows their stuff.

last question: where to buy gears from / good price and quality parts. I hate buying parts that are not what you were expecting, or wrong fitment. discount auto ordered motor mounts for my pontiac 7 times before they got the right ones in. added an extra month to my build for no good reason.
thanks for the help in advance, you guys realley make the diffrence here vs other sites
 

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my friend had a 3.73 on his auto. and the rpm was high as he cruse on the high way, and exhuast system it will be bothering. thats why he changed to 3.07 and that where he is happy now and enjoying the car now.
i guss 3.07 is a good choise, with a agood cam you can enjoy both the top speed and the launch over your 2.59 i think.

;)
 

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Check your rpo codes in the center console for what ratio you have.

I'd say 3.54, thats what i was going to go with, or still am, when i have the funds available. if not then probably the 3.07
 

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Discussion Starter #4
Check your rpo codes in the center console for what ratio you have.
im not exactly shure where to look? my car has been apart a fiew times and Im shure some pieces of it have not made it back succesfully, like the inner liner for my arm rest compartment, :crazy: I keep loosing stuff down the sides of it:rolling:

I wonder if there is a way I can determine my rear gear ratio by speed and rpm in a certan gear factoring in slippage from the torqe converter?

I was thinking 3.73 gears would be kinda steep in a auto 4 speed.
 

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You can use this tool to figure out your rear end ratio.

http://wahiduddin.net/calc/calc_speed_rpm.htm

The 3.07:1 would certainly give you more spice (assuming that you have the 2.59:1), but you'll probably enjoy a 3.45:1 a lot more. The 3.73:1 may be too much for primarily street use.

Steven
 

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I have 3.73's in mine and LOVE them. Now I don't drive it daily but in the last 2 weekends I have gone on longer trips with it 20+ miles and the rpms didn't concern me one bit. My dad had 3.73's and he went to 3.54's and is really happy with that so it is all about you and what you want. At 70 your looking at about a 300 rpm difference. Pm Coolblue he bought my old rearend and swaped to it from 2.59's and said it's really what he was looking for so there are tons of ways to go you just need to decide which is best for you. Look under your console lid (just open it and look at the bottom side) there should be a sticker with a bunch of letters and numbers on it. If it's still there we can tell you what gear you have.
 

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my car is manual trans, came stock with 3.07...put in 3.73 gears and had difficulty hooking up on street tires...changed to 3.54 (3.45 are easier to find) and all was good till the engine grew some hair, now 3.33 might be better...your auto benefits from ''torque multiplication'' till the converter locks so, for street use w/ stock engine & street rubber, the 3.33 or 3.45 should work.
 

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Gears are one of those topics(like cam sizes)....that if ya ask ten people, ya get almost as many answers..........The nice thing about overdrive transmissions like we ALL have these days....is that drag oriented gears like 3.73's and even 4.10's (believe it or not) are "plenty drivable" (even on highway trips) and don't usually hurt gas mileage much more than a couple miles per gallon.......heck, cars back in the 60's used to come with 3.55's, 3.73's and 4.10's and they diddn't even have overdrive transmission's......And I completely understand that gas was crazy cheap, but this is part of the reason why many people still think that these ratios are a pain in some reguards, like they were in the old days.....but they're really not bad at all......Except mabe for one of those "regular car people" that want to be chugging along at 70MPH with the car lugging at engine RPM's that are barely above idle:laughing: .........Get the gear that best suites your cars intended usage........for the engine you have, and A4 automatic transmission's ratios.....anything between 3.31's, 3.45's, and 3.73's will work GREAT......max starting line performance will be had with 3.73's if , and this is a BIG "if"....if you plan on running stickier than stock radial tires(IE: A drag radial) .......with regular tires that "will" easily spin, performance will be very comparable between all the ratios mentioned..........Just my two cents here: I personally always go with 3.73's in A4 Vettes....and 3.73's to 4.10's in 6 speed cars...........good luck with it...............Joe:thumbsup:
 

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Did someone mention my name? :laughing:

Like raid said, I went from the 2.59s to his old 3.07s and there was definately a difference in the seat of the pants. (although I haven't run it down the dragstrip yet to see how much of a difference it actually made) With the 2.59s I was barely able to get the tires loose, now its easy. With the 2.59s I was barely able to get the tires loose, now its easy. So I am very happy overall.

Interestingly though, my city mileage improved by about 2-3 mpg (19-20mpg now) and my highway mileage decreased by about the same (25-26 mpg now).

Now, I was working on a tight budget so used gears were really my only option...f I could have found something a little steeper, I might have bought them instead.
 

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from what i was told, my car has 4.10's and they are loud,sounds like its a s/c rear end (i've already changed the fluid!) if i had to run the 60' i would do it in an honest 10 sec cuz id spin right throu the 60 foot,my car catches traction in mid second gear,and i have futura gls, wich isnt that bad of a tire but in tryin to saveup for that sticky icky!
 

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from what i was told, my car has 4.10's and they are loud,sounds like its a s/c rear end (i've already changed the fluid!) if i had to run the 60' i would do it in an honest 10 sec cuz id spin right throu the 60 foot,my car catches traction in mid second gear,and i have futura gls, wich isnt that bad of a tire but in tryin to saveup for that sticky icky!
Might have a Richmond gear set in it........man are they loud most of the time(in the car).....and/or if the shop dosn't get the power and coast depth of the ring and pinion set just right, they whine pretty bad......yea, throw some MT et streets on there and hold on.........Joe:thumbsup:
 

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I have 3.07's in my 84 auto, and it feels to me that it needs more gear. I really like it on the highway, but when I get on it, it just doesn't feel like enough. I do a ton of highway driving, so I'm thinking about going for something in the range of 3.54.
 
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