I just bought a 94 Z28 with cold air and shift kit. I was wondering what everyone thinks I can run in the 1/4 mile, just curious.

 

the shift kit doesnt do anything to lower ET's... but I would have to say low 14's. MAYBE 14.0 w/ just the CAI.

 

et deends on traction,weather,elevation.
Where do you live? whats the weather normally like?

anywhere from 14.1-13.8 if i had to make a WAG

 

depends on if your runnin 273 or 323 ...id say low 14 high 13's is a pretty safe bet

 

When I bought this car it has z rated tires in front and not back, I was wondering if I should change the z's to the back or not?

 

It wont make a big difference, but yeah, you should. Generally Z rated tires are more stout then lesser rated tires, and seeing as these are the ones that are getting the torque and power, you should probably put them on the back