SJPajak

I am currently running a 3.55 gear ratio in my 91' gt and im thing about moving to a higher gear such as 3.73s, 3.90s, or 4.10s. can anyone give me some insight as some pros and cons in doing so. any suggestions?

jason5641

I just put 4.10 in my 90 gt. Much improved over the stock 3.27. I have an AOD and its just a weekend car though. The speedo gear is still a little off too- even after switching it out.

It definitely improved the "fun" factor.

SJPajak

Did you put them in yourself or did you have them put in? what brand did you go with and how much?

jason5641

Ford racing. Got them off ebay for $140. They was a place advertised in Fast Fords that had the gears and the install kit combined for $260. I don't have the mag in front of me though. I bout the kit separately for about $100.

Then I had them done by a professional. there are some things I would do but from what I've read this is best left to someone who has done them before.

The posi rebuild and the install was $525 but things seem more expensive here in SE Pa.

nitrous_bob

you will NOT notice much difference by only going 1 gearset, so if you want to feel it, go 4.10 or don't bother

i never use anything but 4.10's, all the bad things you hear are NOT true.....

1) you will NOT have to shift into 5th in the 1/4 (you should trap about 5200 rpm which is perfect)
2) you will NOT have a huge drop in mileage over any other gear swap (it is directly comparable to how u drive and the gear, 4.10's will however allow you to be in 5th in the city reducing fuel consumption but overall will drop... nothing to worry about)
3) you will NOT do 3k at 55 mph (more like 3k at about 75 mph)

i have no cons whatsoever... all pro's, my '89 went 13.20's w/ 4.10 and exhaust, then added 75 shot and it went 12.50's on et streets

to correct your speedo, you really need a 6t drive gear on the shaft w/ a 20t on the end of the cable

23t are NOT ford parts and WILL wear out, i think your '91 has an 8t in it, and can only be properly corrected to 3.27

if it is a 7t, then a 23t will get you right, but expect to replace it often

67fire

Auto or manual? Do you ever plan on a FI system?

Eric

mjr46

put the 4.10's in and be done, I'm soon to do it, in the fall possibly