Exhaust advice

[1984gmck1500]

I just did a header back system on my 84 305, and I love how loud it is, but I don't think my neighbors or the law will, are glasspacks legal? I want to keep it somewhat loud so I thought about the single chamber mufflers but I need something that's 18inches that I can replace a pipe with, any advice would help out a lot.
By the way I live in El Paso county Colorado Springs co.

Thanks!