going to upgrade from 272 hks to the 280's..being that these two cams have the same lift only increased duration what will be the affect on my aem tune/AFR's? wondering if it will be that much other then more power since the lift is the same with increased duration will allow more air and fuel..anyone? nothing else is going to change on the motor so i will be able to see what the power gain is as well once dynoed.

 

Yes, it will change things a bit. You will also loose more vacuum. The longer duration allows more air so more fuel is needed (presumably) so I would start saving for a tune.