When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
There are a few different part numbers..(someone on here will have the numbers, don't have them with me at the moment) But the LS6 intake will be flat on the bottom and an LS1 intake will be raised slightly down the center on the bottom.
Also, an LS6 intake will not have an EGR hole on top right behind the throttle body opening. The C5 LS1 intake will not have this hole either as there is no EGR on the C5. But, if it does have that hole, then it's an F-body (camaro/firebird) LS1 intake.
Those are easy ways to tell the differences by looking...