Was wondering if it's safe to add 3:73's...

[SC90_Pete]

I was wondering if it is safe to add 3:73's to a stock engine and trans before I do any other mods. Also I realize I'm going to need the speedo recalibrated, anything else besides that. Also do you really notice that much of a difference with 3:73's on an AOD?

[Thomas A]

Yes, you'll be fine. The gears don't directly effect the tranny or engine. Gears is one of the best bang for the buck mods you can do. I'm sure you'll notice quite a bit of difference going to 3.73's, esp on the low end.

Thomas

[Darkside]

Yup!:D

[David Neibert]

Very good choice for your first mod, you'll really like them. All you need to fix the speedo is another plastic gear, 21 tooth I believe. SCP sells them and it only takes a couple minutes to install.

David

[SC90_Pete]

thnx for the info guys! I'll be getting the 3:73's this christmas, I can't wait.

[SC90_Pete]

one more question about the 3:73's, how are they when driving on the highway. I know 4:10's on a mustang are bad for highway driving so I was just wondering if the 3:73's are safe on the highway. Don't want to be running the engine in a high rpm range for extended periods of time. Thnx in advance.
-Pete

[Kurt K]

You'll be fine on the highway (err, except for the lower mpg). I've got 3.73's and a non-lockup convertor and didn't have any problems driving 3200 miles round-trip to Floriday this year. I averaged about 75-80 mph. It's been a while since I had stock 3.27 gears, but I think 70 mph was equal to about 2000 rpm. All things being equal, 3.73 will put you near 2300 rpms at 70 mph. EVen if the rpm is different, you can do the math:


new rpm = (3.73 X old rpm) / 3.27

[SC90_Pete]

Whats the typical installation fee to install 3:73's? A buddy of mind told me he was quoted 500 dollars, anyone else heard of any cheaper?

[Kurt K]

I was getting prices around that also, and that was with me removing the pumpkin and bringing it to them. So I decided to buy a new 99 Cobra pumkin from Ford with 3.73's already installed (less than $700). I didn't have to worry about any down time either.