Will I have a problem putting on 275/18/40 tires on 18x9.5 rims on the front? and the same ones on the back? On a stock 2001 v6 camaro?

 

A 275/40-18 tire is 26.66" diameter. If your car came with 215/60-16's that were standard on the V6, or the optional 235/55-16's, they were only 26.16" diameter. Going to a larger diameter tire makes it more likely they will rub, depending on the offset of the 18x9.5" wheels. The stock tires on the WS6/SS models was a 275/40-17, and that's only a 25.66" tire.