calebchoson

I was checking on my rpo codes and i would like to know what the 3.54 rear axle ratio is. Is this just the ratio on the rear end or on the transmission gears as well?

STL94LT1

You won't find a rpo code for 3.54 gears in a C4. They didn't come with that gear ratio.

tobijohn

I don't know what the RPO code is but if you've got a six-speed and nobody's tampered with it (and if they did then knowing the RPO code wouldn't do you any good anyway) then you should have 3.54s. Here's a couple links with more info:

http://www.corvetteactioncenter.com/...9/89specs.html
http://www.idavette.net/facts/89.htm

calebchoson

so its only the rear axle ratio and not the gears, understood. How much better is the 3.54 axle ratio than stock, is this used to be allowed higher gear ratios for mods?

Strick

My 92 came from the factory with GHO 3.54 ratio Ax. It's a 6 speed Dana 44. It's right on my build sheet and stamped on the dif housing.

STL94LT1

Not that it makes a big difference. But, all ZF6/D44 C4's came with 3.45 gears, not 3.54's.

Strick

I think you are wrong. Mine came with the 3.54s It's even on my build sheet! Maybe I have the only one. It might be worth millions! ...............NOT...............

Z-07 freak

3.54 was used in early 6-speed production for the `89 model year.

BowTieBlood

How much better it is, is all going to depend on what gears you have stock. Post your rpo codes and we'll be able to tell you what you have, and some guys should be able to tell you what you'll gain as well

BowTieBlood

Hope this doesn't repost, apparently it didn't work the first time

How much it improves your performance is all going to depend on what gears you have stock. If you post your rpo codes we can tell you what you have stock, and many member will be able to tell you of their gains with the same set-ups as well

marlon88

3.54 ratio came in all the ZR-1`s 90-95 , I read that there was an option that you can have the 3.54 as a performance ratio for the ZF6 equiped vettes .


When I bought my Dana 44 it came with 3.54

*89x2*

This IS the correct answer - and as also mentioned, the Zr1's got it as well.
Late 89's w/ ZF6 got the 3.33's and then in 90, a switch to 3.45's from then on...

Enjoy

BlackbirdZ07

My '92 also came with a 3.54 rear end from the factory (code GH0). I'm not sure what what years it was available, but it WAS optional on six-speed cars.

calebchoson

Here are my rpo codes AC1,AC3,A09,AS8,BGR,B4D,CC3,C68,DL8,D4L, D98,E5Z,E9Z,FE7,FX3,JH0,G87,GH0,J55,KC4, K68,L98,ML9,MN6,NA5,NK4,OAI,UJ6,UO4,UU8, U52,VO1,V73,XAU,YAU,Z51,1AA,1A2,1SR,245, 731.
Some of these may be off by 1 letter, sorry but the pen was messing up, and I believe there was a few more.

Mr Mojo

As stated above it is also stamped on the diff.

h rocks

Negatory...depends on the year. Many/most 1990+ L98 ZF's came with 3.33's. I agree with one of the other posters that for a while in '89 the ZF's came with a 3.54. (there may have been a few other anomalies, as a friend has an '85 that removed his 3.54 gear, and installed a 3.73. No, you can't have his number as I'M first on the list!)

calebchoson

why change to 3.73?

BowTieBlood

I'm guessing that's GH0? According to this site, that says 3.54 gears.

http://www.corvetteactioncenter.com/...89/89prod.html

I'd stick with those if you got 'em

CFI-EFI

Or maybe the code is GH0, instead of a misprinted, JH0.

RACE ON!!!

BowTieBlood

:shocked: didn't see that one