I have the vortec intake which is the main reason I am not going to just switch directions. The website claims they are a direct replacement. When I spoke to Engine Tech direct they tell me they are made to the same specifications as factory. Here is the photo on rockauto that looks like a true vortec style chamber. Not sure if the intake port is the same, but it looks like it. Yeah, the QC is right down the way. I actually live about 1/4 mile from the county line.