Ls6 Intake
this has been covered a billion times, but here is the short easy answer, on the bottom of the intake, (the floor) the ls1 is concaved, meaning the floor is actually pushed upwards towards the runners. The LS6 intake is flat on the bottom. Thats the easiest way to tell by looking. most of the ls6 intakes do not have the hole in the front behind the throttle body that the egr tube goes into. there are some that do, but they are not that common. If you still are not sure on the intake there is a number cast into it, believe its on the passenger side of the intake,,,,,,, post that number and we will be able to tell you for sure.
