lil history ---Mods, new injectors, cold air intake, flowmaster no cat exhaust, no backseat, AC removed, new plugs, wires, cap, fuel pressure reg, intake gaskets, 103,000 origin miles.

http://www.napaonline.com/Catalog/Re...122+4286674454

link to the Napa part above (3.90 gears)

i was doing a little research and found these, i'm trying to buy a different gear ratio to make the 6 seem a little faster and make it more fun to drive here in town...do drive on the highway occasionally, will these fit? plan is to buy them and have a shop put them in since i'm a college student, any thoughts or advice, thanks in advance guys.

 

What gears are in the car now? If they are anywhere between a 3.08 oto 2.14 then you will have a 2 series differential and you will need a 3 series. If you have 3.23 to 3.73 gears then you already have a 3 series. You will also need a good insallation kit.

I didn't see a price on those gears. Are you set on a 3.90 or would a 3.73 work just as well?

Here is a 3.73 that will work on the 2 series differnetial. http://www.ringpinion.com/b2c/Produc...nd_Pinion_Sets
Here is a 3.73 that will work on the 3 series differential. http://www.ringpinion.com/b2c/Produc...nd_Pinion_Sets
Here is the installation kit that I would recommend. http://www.ringpinion.com/b2c/Produc...rce=DiffWizard
And this differential. http://www.ringpinion.com/b2c/Produc...ukon_Dura_Grip

 

They are $200, i believe they are 3.23s, because that's what came stock, so would those from napa fit? thanks for all those recommendations, i can get a discount going through napa, and im not set on 3.90 i just heard 4.10s arn't good to have when highway driving and i do very little but sometimes have to

 

Since the car is an auto and has stock gears then they are 3.23's A step to a 3.90 is going to feel nice, but IMO it's not a crazy jump since you have OD. When I had my 90 Stang GT I went from 2.73's to 4.10's with a 4-speed auto. I loved it-it was like getting a differant car and it dropped about a second off my 1/4 mile times. It was ok on the freeway, but my top speed went from about 140 to about 105-110-no biggie I don't like to go that fast much anyways.

 

Yes, if you have a 3.23 now those gears will work. Just be sure that they are made in Italy and not Korea. If they are made in Korea then pass on them and get something else.

There is very little difference between a 4.10 and a 3.90.

 

so should i just go with the 4.10s then or just go with the 3.73s to be safe? and then ill need a instilation kit and will i have to get a posi track or will i b ok without it? thanks again guys

 

I would go 3.90 or even 4.10. To me 3.23 to 3.73 is not that huge of a jump for the money. Yes an LSD/Posi would be a great idea, but if your not going to be makng crazy power and don't care about two even patches of rubber then you could stay open diff. If you have the money and the rear end is going to be apart anyways then I would install the posi unit at the same time.

One thing I do recomend when running steaper gears is an external trans cooler. They are cheap and easy to install. I did not do one on my Ford AOD and with the gears, shift kit and beating on the car alot the trans went. The 700R4 is stornger in stock form then the AOD, but any auto trans will live longer with cooler fluid.

 

Most people are happy with the 3.73, but that is all subject to personal opinion. Chances are you will be spinning one tire a lot with the gear change, so the LSD would be a good idea. It's not required. If you decide to go that way then I recommend that you stay away from the Auburn. I'm guessing that NAPA is probably only going to have the Auburn, and their installation kit will probably be a reboxed Ratech kit, so you will need to go somewhere else for the LSD and the installation kit.

 

Stock '92 3.1L auto is supposed to be 3.42:1. I'd go 3.73:1, not 4.10:1