I have a '00 1500 Z71 with the 5.3 in it, and I'm wondering what the stock piping size is that goes in/out of the muffler?

I'm going to replace the muffler I think, so I need know what size to get. I am thinking about getting a Hooker Max Flow Muffler. In a test I was reading it flowed much better than the Aerochamber, 7Db quieter at idle, 4Db quieter cruising at 2k rpm, and 6Db louder at WOT. I've heard some clips on other cars and it sounds really deep, so I think it would be a good choice. What do you think?

And how about lengths? They have 18" and 26" total lengths.

Thanks for the help.

 

2.75" in and out

 

go 3" in 3" out, length depends on how loud you want it.