I'm debating if I should put 373 or 410 gears in my 98 Z28. Its automatic so I've got overdrive on my side. Anybody have any opinoins? Also if the code GU2 is in my door jam that means I have a 2 series carrier right?

 

Everyone will tell you the same thing:

3.73 for an auto
4.10 for a manual

 

Yes, GU2 is the 2-Series carrier with a 2.73 gear.

 

then I'd definitely go with 3.73 gears. That will be a big difference for ya.