GatorGreg

I saw in another thread somewhere that the vert's version of the performance axle ratio was only 2.73 instead of 3.07 and that it came with the designation "GU2". I checked my car and "GU2" is listed with all the other RPO codes on my center console lid. But when I checked the corvette action center here

http://www.corvetteactioncenter.com/...88/88prod.html

it doesn't list GU2 for 1988. It has it for other years like 1989. Can I assume it's just an oversight on that website and that my car definitely has the vert version of the performance axle? Does anyone know what percentage of cars got this option?

pologreen1

no offense but, does it matter? I would say if your car is stamped something other than gm1 than you don't have the gross 2.59's but either way it is really a tiny difference performance wise.

A small chance someone changed the console lid. very small.

GatorGreg

It does matter to me a slight bit - it would make me feel good to know if my car was originally optioned with performance in mind - however meager the additional benefit may be. I agree the difference btwn 2.59 and 2.73 is more pyschological than tangible

pologreen1

I think you have 2.73
FWIW

Pete K

Coupes got the 2.59
Verts got the 2.73
If my memory is correct.

UNCLEBILL

I have a 1990 Vert marked with...GU2... is for 2.73 and Verts to my knowledge got the 2.73's.

Z-07 freak

That is correct (for `86 -`93 verts).

As for your RPO sticker being a match to your Vette... It's as simple as checking the VIN on the RPO sticker to see that it matches your Vette's VIN.

GatorGreg

Thanks for all the responses guys but I'm still kind of confused, sorry. From some of the comments above it almost sounds like some are saying they equipped ALL '88 auto verts with the so-called "performance axle" 2.73 as standard equipment instead of the 2.59 that came on coupes. What I'm trying to confirm is that 2.59 was the base axle that came on both coupes and verts, and only if you checked off "performance axle" on your order sheet did you get the 2.73 if vert and 3.07 if coupe. In other words, did most '88 verts get the 2.59 or did ALL the verts get 2.73?

Z-07 freak

For MY 1988 w/ autos.
2.59 standard for coupes & verts
2.73 optional "performance axle" for verts
3.07 optional "performance axle" for coupes

c4cruiser

Vert's with an A4 got a 2.59 gear ratio (RPO GM1) as standard. The performance axle was a 2.73 (RPO GU2) and there will also be an RPO G92 (which simply denotes the fact that there was a performance axle ordered) shown with the GU2 code.

From this page, it shows G92 as being a 3.07 axle and there is no specific mention of a 2.73 for 1988. Also look at the bottom of this page in the gear ratio parentheses. Could be that the 88 vert was unique for gear ratios. Just like different mufflers based on body style or gear ratio (see paragraph in the first link).

But these pages in the links may not be 100% correct. You can also check the Corvette Black Book

GatorGreg

Thanks freak and cruiser. My lid definitely says GU2 which denotes the 2.73 so it sounds like the action center site may not have complete info. I'll double check the lid tonight just to make sure the VIN matches up. Also, I'm gonna order the build sheet/sticker from the Corvette museum and it should say on there what all the car was equipped with.