Try these guys:
http://www.heartthrobexhaust.com/
Mandrel bent 2-1/4" aluminized pipes. Your choice of muffler type and tailpipe exit location. At least that was the case on my 82 C10.
I got mine from this distributor at a very low price.
https://www.autoaccessoriesgarage.com/brand/Heartthrob-Exhaust
Edit: Whatever you get, make sure the pipes are
aluminized. I bought a kit from Summit for a 69 C10 many years ago that was not aluminized. The pipes were already starting to get surface rust on them when I opened the box.
And, man, those muffler shop "crush bends" can easily reduce a pipe's effective volume by 30% or more. Same is true of some aftermarket stock replacement mufflers that neck down the pipe internally by 1/2". After all, the easiest way to reduce sound is by "restriction".