I have an 81 z28 the gears are all stock in the rear and i want some opinions on what size gears to upgrade them to? Never messed with the gears so I'm kinda lost here. Trying to gain more low end torque.

 

be a good idea to know what you have first. current gears, is it an auto or manual and what kind?

 

And what kind of driving do you do? If you rarely take it out on the highway, you'll have more fun with lower gears. But low gears aren't very gas mileage friendly (if that's a concern) on the highway if you don't have overdrive.

 

Its an automatic 4 speed 350 tranny with a ratchet shift. 273 gears

 

A 350 tranny is a 3 speed, not 4.

 

I didn't even notice i said 4 speed. Thanks for catching my mistake. For your other response i do mostly city driving, i drive aggressive but never really get onto the highway much.

 

If you're not spending much time at speeds over 60mph, then I'd say to go with something around 3.50-3.73 ratio. The 3.73 being the easiest to find. But be prepared to have your gas mileage reduced by an equivalent amount! Probably lose 30% off your current mileage going from 2.73 to 3.73 gears.
Be sure you have someone experienced do the swap, as they're not just a bolt in and go thing. Need to have the lash set properly.

 

With rare or no highway driving, I second the 3.73's. Lower rear gears multiplies the torque at the wheels, which means the engine doesn't have to work as hard to get the car moving. I wouldn't expect you to get worse gas mileage driving around town, actually it could get better. But watch the right foot, as lower gears are more fun to play with.