Who makes a quiet yet small muffler?

[Jayschevy]

I have a bagged LWB 71 with a 350 motor in it with headers. I'm in the process of redoing some things like my rear suspension and converting from a LWB to a SWB truck. Space will now be very limited in the rear of my truck due to having to mount air tanks and compressors.
Because of this, I need suggestions for a quiet yet very small (length & width) muffler that I can mount in the area under the cab.
Again, I'm looking for something small and quite that'll not wake up the neighbors.
Any suggestions would be very helpful. Thanks