Headers for a 454LSX

[69x22]

I just bought a 454 LSX for my 57. It came with lS7 heads from GM.
A lot of headers I look at have a notation that says except for LS7. Is it because of port design? Will 1 7/8" cover LS7 and the other LS heads?

[Ultimate Headers]

69x22...

Our headers/flanges will work just fine on the LS7 heads!
If you want, check out the headers we built for Stacy David and his Cheetah which also has a 454 LSX motor!
http://i63.photobucket.com/albums/h156/BLK3V/Cheetah_zpslcsiokvd.jpg
We are heading out to PRI today, but if you want to contact us next week, we would be happy to answer any questions you may have on our line.
www.ultimateheaders.com

Thanks,
Jim