Does Heavy Half mean my truck is fat?

[79gmcsierragrande]

We don't have smog checks here so the guy who owned it before me put on headers and glass packs, ran it duel, and took off all of the smog stuff including the cat. I don’t like the sound or the smell of it so I'm putting it all back and I'm looking to improve it with some more modern technology. They do smog checks for a reason and I like being able to breath.