I have a 98 z28 and have been doing some work to it and everything was fine until i had my automatic transmission worked on so it would shift firmer i tried launching the other day and no matter what once it goes over 3500 rpm the wheels start to hop instead of getting traction no matter what i try i cant get a good launch without the wheels hopping, it feels like something is going to break so i need advice before something does. i checked the shocks and rear suspension everything seems fine although they are still the original, also i have falken grb 285/35/zr18s on the rear with stock z06 wheels are there any parts that i could get to fix this or is it the shocks, or tire pressure.

mods: k&n filter, headers, cat backs, 3.73 rear end, hypertech program

 

You could start off by installing stiffer Lower Control Ams & bushing, and possibly the torque arm. The stock hardware is on the flexible side and can't handle hard shifts too well. If the shocks are old you may want to replace them also.