SteveSkal

I'm trying to choose between these 2 gears and I think the deciding factor is going to be rev's on the Hwy, so who has a calculator that can tell me what RPM's will be at lets say 80 MPH with both ratio's. I have a 94GT 5 speed and rear tires are 255/45/18. Thanks

Shelty

If my memory serves me correct, you'd be running around 2400rpm at 70-75mph with 3:73s. but dont hold me to it

cortlan

I've got 3.73's in my 94 gt, it's an automatic but at 80 i'm runnin about 2600-2700. 3.73's seem to be a good choice in my book.

SteveSkal

and if I remember correctly the 5 speed has a steeper overdrive gear than the Auto so that should even bring the RPM's down a little more.

USMC1775

Take my word for it Steve - go 373. There really isnt that great of a difference between your choices, so you might as well go with the higher gear, seeing as its further from stock. I drive on the freeway every day, and I dont have any complaints

SteveSkal

Yeah, I know everyone is going to recommend the 3:73's over the 3:55's from a performance/acceleration standpoint, but I just want to be sure I'll still have all my Hwy speed. I drove my old fox body from NY to CO with 3:55's, at least 80 MPH or better the whole way, could I still do that with 3:73's?? I'm sure I could but will my engine hate me for it.....

jzandy

im assuming you still have the 5.0 engine in it? well if you do, nothing can hurt that engine, get the gear they put in buses and run it at 5,000 rpm all day long.

cortlan

Ya that would even make yours better! seriously I drive highway easy going 80 or so and I seriuosly haven't noticed much difference at all. I haven't calculated MPG exactly yet but it should be fine! 3.73's IMO

USMC1775

I always cruise at 80 ( socal freeways - youll get run over if youre under 75 ) at about 2600 rpm... no prob.

One trip to havasu all highway I averaged 26mpg my best, my average tank with city driving is about 20mpg

OnyxCobra

3.73s are a lower gear than 3.55s



Are you sure you're running a 255/45-18? That is taller than stock so your RPM will be a little lower than normal w/ that size.


stock tire diameter + 3.55s @ 75mph = ~2400rpm.