I went from 2.73 to 3.55's I'm very pleased. Even with an auto . I almost took off a full sec. from my time slips. with no other mods at the time. Gas milage didn't suffer either. only lost about 1-2 mpg.
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91 LX Conv. 5.0 FRPP- shorty headers,Rebuilt AOD with wide ratio kit,3.55s, Flowtech H-pipe, Dynomax Cat-Back, Explorer Intake, Explorer Injectors, 3/8 in phenolic spacer, C&L 73mm Maf, Moroso cold air, Trickflow Valvespring,cloyes true roller, Steeda 1.72 RRs, Strut tower brace, air pump eliminator pully, Blackmagic electric fan,
Just get the 3.73's, because say if you were to get the 3:55's and lose to another mustang that has 3:73's. THEN YOUR going to want 3:73's all over again over those pesky 3:55's. Do it right the first time. <----- Actual story.
My friend and I had both mildly stock 5.0s and I had 3:55's and he had 3:73's. He ran a better et than I did and I had more mods. Get the 3:73's.
im thinking of going with 4.10's in my 89 LX 5.0. The car is all stock except smog removal. Unfortunately my car has an AOD so i was told to go with 4.10's. Just wondering how big of a bite this will take out of my gas mileage and any other problems i might incur...
Originally posted by smitty will a 2001/2002 indipendent rear sus 8.8 diff carrier swap to a 89 gt??
NO it won't, the 99+ rear end is 3 inches wider than the fox body rear end. And the 94-98 is 1.5inches wider than a fox body rear end. Also, the jounce travel on a 99+stang for the solid rear end is 1 inch further up than the fox body. You might need that extra clearence for the tires. I measured the IRS from a 99 cobra (rotor to rotor) and it was 1/4inch wider than than the 99 GT rear end.(rotor to rotor) but that could have been user error on my part, I was in a rush.
Just yanked the 2.73's and replaced with new 3.73's. Very nice...car pulls throughs every gear...I actually use 5th now. On the other hand, I was surprised that I actually have more control through the gears. It just gets up and goes. With the 2.73's I'd get sideways and lose time when taking off the line. The 3.73's just grab and GO...!
Here's another vote for 3.73s. You won't be disappointed.
I tried 4.10s first (5sp - all street, no racing...well, ALMOST no racing) and wasn't happy with how high I was reving out all the time. 3.73s were just what I was looking for.
I have a '95 vert GT 5 sp with just an intake and U/D pullies. I just went from 3.08 to 3.73 gears. Gas mileage is mostly from highway commuting, but actually improved a little from 20 to 21. Pulls much harder from 3200 RPM's on up to redline. Overall, I'm happy with the swap.
However, from takeoff, I was expecting "holy crap" torque and to be pushed into the seat hard to the point where it would be difficult to sit forward at all. I really don't notice that much difference from the 3.73's until I get to about 3200. Then that V8 starts to pull hard, but still not "holy crap". Is this just from the extra weight of the 'vert? Should I have gone with 4.10's? Do I just need more HP?
Get the 3.73's dude............ You will not be dissappointed. I'm on my 6th Stang now and everyone that has been driven on the street had em'. For the $$ it's the best thing you can do for your car. 3.55's are a waste of time and $$ unless your car has a turbo or is supercharged, and 4.10's are to much on the street for everyday use. I went from 3.08's to 3.73's in my car now and there was only about 300 rpm difference at speed.The really nice thing is the pull. Mine has a 347 so I have a lot of torque, but even with a slightly modified 5.0 you will love the difference.
carrier swap? 
3.73's...NICE...! 
