I ordered some AC air filters for my Duramax, A1618C, but was sent the A1518C. I believe the A1518C is for gassers, like 5.3 & 6.0L. But looking at them the appear to be very similar in size and media. The only difference appears to be the glue lines on the Durmax filter.
Does anybody know if there is any other difference?

Send them back. Dont use them. The glue lines are there for a reason. They keep the filter rigid so it dont get sucked into the turbo.

I was planning on giving them to my brother who has a 5.3L Still wonder, if that is the only difference, why doesn't Delco just sell the A1618C for both applications?
But thanks for the response.
Eric, when are you going to up-date your web-site?

LOL, I'm working on the site, totally different site. Man is it time consuming. Not sure why not just one filter, wondered that myself.