6 cyl vs. 8 cyl crossmember differences

[Steve Cole]

This question came up in the LS swap section and I wanted to post it here for more visibility. Does anyone know the difference between the 6 cylinder and the 8 cylinder engine cross members ? Another member couldn't get his LS motor to fit and the maker of the engine mounts he was using said he may have a 6 cylinder crossmember instead of the 8 cylinder one. I'm wondering if I have the same thing. How can you tell the difference? Thanks!