KcMstang

I have a 5spd and from what I'm learned from searching is that they come stock with 3.55 gearing. I recently installed 20" Shelby rims and lost some of the power that it had while sitting on the stock 17s, which was to be expected. Now this is my DD that does see highway almost every day. Should I bump up to 3.73 or 3.90 gears, I believe 4.10 would be too much.

Thanks,
Kevo

Nuke

You should be able to verify your gear by reading the tag on the diff cover. If not, then there's a code on the vehicle data sticker on the drivers side door frame. I'm not sure what the '05 manuals came with but based on your described driving style, if you have 3.31's then I'd suggest the 3.73's UNLESS you're really looking for a major change. If you have 3.55's then the 3.90's or 4.10's would be a noticeable difference. I hear the 4.10's rock but I'm not convinced they're for everyone.

KcMstang

Yeah, I was kind of thinking that 4.10s would be a little overkill on the highway. I don't want to kill much top end!

BruceH

Delete...

brunobluto

kevo, i did the exact same thing with my 05 manual. btw, all the manuals that year did come with 3.55 gears. i put 315/35/20's on mine and quickly noticed the drop in torque just like you did. i bought a set of 3.90's and installed them myself. it made the performance and rpms in each gear nearly identical to what it was running 17" wheels and the stock 3.55 gears. its ok, but i want more. i will be installing 4.30 gears in the next couple of months. with 20" wheels, 4.30's are like running 4.10's with 17" or 18" wheels. bottom line, if you want it to run just like before, go with the 3.90's. otherwise step up to some 4.10's or 4.30's.

mygt500

I would go with the 4.10! You have a 3.55 and to go to a 3.73 (FI or not) is a waste of money IMO....but to each his own!

Stkjock

The 05/06 5spds came with 3.55s as OEM gears.

what diameter tire are you rears?

the jump to 3.73 is not that great, I'd go 410s, with my shorter tires I see 2500 rpm @ 65-68 in 5th, a taller tire would drop that some, the rim size is not relevant.

KcMstang

My rear tires are 285/30/20 which is what AmericanMuscle suggested. With 4.10 gears what kind of rpms will I see when doing 85 in 5th gear!