I just bought an 89 5.0 5speed trunk car. wanting to change rear gear, cant decide between 3.73 or 3.55 leaning towards the 3.73 gears. but dont want to comprimise driveability TOO MUCH. car has 17x9 wheels and 225/45/17 tires also thinking of going with a auburn pro posi unit!? What do you guys think any help would be great!

 

Since this is technical related to your fox body, i'll move it there to get you a better answer

Btw, welcome to the board!

 

i say go with 410's haha. as long as you dont mind the hit in the gas tank go for 373. i could care less. so i am gonna go with 410.

 

I'd say go with the 3.73's. Especially if you want to add nitrous, blower or a good H/C/I setup later down the road. 4.10's would be overkill at that point and make 1st,2nd, adn parts of 3rd tractionless.

 

I am in the same boat... I purchased 3.55's and I had an AOD tranny in my car but recently did a 5 speed conversion. needless to say I am selling the 3.55's and just purchased a set of 3.73 for the car. I can't wait to do the swap. I wouldn't go bigger than 3.73 personally because I use the car daily. I put a set of 3.90 in my 78 Trans Am and the car REVS a little bit much but she launches like a TIGER!

 

IMO go with 3.73:1 gears

 

Use 3.73's and I would run far away from the Auburn.....use a Ford Traction lock and add extra clutches.

 

I just put 4:10's in my 88 5.0 wit a auburn posi....let me tell ya... they're awsome. I would have to say that it really depends on how much gas you want to use. Im not sure if its true but I heard that for every gear ratio you go up it tacks on 200rpm. So from 3:73's to 4:10's ur addin 400? I think it worth it. But I would would say def. go with atleast 3 73's. You wont regret it!

 

3:73 gears will be great, so will 4.10 gears, Personally I would opt for the 4.10 gears, as the 3.55 gears don't help n-e thing greatley. If you have enough cash buy a World Class T-5 Transmission for it, This tranny is sweet and will be alot stronger then the stock unit and is optainlable from summit racing.

 

If staying Natural aspirated go with 4.10s.

If planning super or turbocharger go no more than 3.73 so you can take advantageof the midrange torque.

Rus

 

3.73's are a good all-around gear set

I got a set of 4.10s installed in my 91 (275/50R15's) but I yet to try them out cause the motor is still sitting in the gargage.

Unforntuately a useful comparison is moot since the old set-up was a 10:1 302 with erson X-cam clone, Edelbrock 5.0 intake and ported E7TE stockers.

Now engine is 11:1 347 comp cam, AFR 185s and Edelbrock Vic 5.0 intake. and the car has been lightned up a bit since the 302