gears

I have a stock 02 z/28 and am looking for information on what would need to be changed if I were to change from 2.73 to 3.42

You need a new carrier (3-series, in place of the 2-series that came with your car), new gears (you can get thicke 3.42r gears that will fit the 2-series carrier), and an install kit with, bearings, shims, crush sleeve, seals, gasket, lube and limited slip additive. Might want to throw in an aluminum rear cover with pre-load bolts for the bearing caps. Then you need to get your PCM programmed for the new gear ratio.