got a question (rear gearing)

[Captain Dirtymax]

hey guys, i've got a kind of troubling question. when i'm on the highway with my '93 Z, i have to turn 2500rpm to run 75mph on stock sized tires and factory 4L60 trans (and yes, it is shifting into OD and the converter is locking up). now from what i've found, at that rpm with the stock 3.23's my car is "supposed" to be running at nearly 88mph. i was using a calculator to figure this out, and when i put in the rear ratio of 3.55:1 it came out to almost dead nuts 75mph. now i'm slightly confused on this because the car is supposedly bone stock. could it be that the car has had gears swapped already???

if so, i'm just fine with it. it'll help in auto-x.

[Blubird]

mine is always around 2500rpm when im cruising at 80 with 3.23s

[TA the destroyer]

your tach can be slighty off, fbody cars rpm tachs are known for being off. i know mine is.

[Captain Dirtymax]

at idle it says 700rpm. and shifts right at redline. don't see how it could suddenly change in the middle of the tach and go back to normal at either end.

[CamaroGirl]

well you never know, pop the cover, count some teeth.

[TA the destroyer]

at idle it says 700rpm. and shifts right at redline. don't see how it could suddenly change in the middle of the tach and go back to normal at either end.
i bet you if you put some kind of scanner on it, it will read a 100rpm off. i can almost garentee it.

[Blubird]

yeah mine idles around the same.something must be off if its shifting at redline

[TA the destroyer]

A4 LT1's should idle around 550-600ish rpms.

[Captain Dirtymax]

well i pulled the cover last night, found out i really do have 3.55's out back:metal:

[CamaroGirl]

badass