I recently dicovered I have 2.73 gears. No wonder it's a dog.
My question is... If I have code GU2 for 2.73 and code G80 for axle posi/lim. slip diff. Do I still have a 2 series carrier? I'm pretty sure it's 10 bolt, I can't get under there to check because I'm away at school and my IROC is lowered. Is it 7.5., 7.625? And should I go with 3.73s rather than 3.42? Thanks for any and all help.

 

They made 2:73 posi's? And as far as the gears you want, if you want the better acceleration and a quicker 1/4, I would go with 3:73s, considering you have a higher lift cam and better heads. Of course if you do a lot of highway driving 3:73s might get the rpms a little high, but traveling to and from college I have no problem doing 75-80, I don't like to take it above 2500rpms over an extended amount of time.

 

I don't know about the carriers but since TPI normally start to peter out by @5000K, I would go with the 3.42's so that you can be in you useful rev range for more of the time. JMHO.

 

Sorry, missed the part about you having TPI. Actually TPIs stop making power past 4500 rpms. Unless you mod it, don't get 3:73s. I made that mistake and w/the cam I have in now it makes no power at the rpms my gears keep me at.

 

Even though now my car makes power after 2500? Out of the hole... it's pi$$ poor, but from 2500-5500~ puts me in my seat.

 

It may feel like you're pulling hard up to 5500. I thought my car was pulling a lot better too until I G-Teched it and found out I only gained a 1/10, from 2:73s to 3:73s, Hooker cat-back and a tune up. But, all it will take is some mods to the TPI and the 3:73s will be fine.

 

by mods... are you referring to siamesed runners, porting the plenum, and a 52 mm throttle body? I've read where doing runners or a throttle body does nothing but put a 305 on its nose. I always thought the heads were what restricted TPI.

 

I'll be honest, I don't know a lot about TPIs. I just know I always read people saying stock TPIs stop breathing past 4500 rpms. So I figured it was the TPI induction itself that was the problem. You might want to ask on the TPI board.