Cletis, do you know how to fabricate and weld exhaust tubing? If so, you can put a connecter between the 2 exhaust pipes in front of the mufflers, what is called an "H" pipe on an 8-cylinder application. That adds torque and reduces noise.
Further improvement is available from larger, quieter mufflers. Loud exhaust systems are very annoying to people inside of and outside of the noisy vehicle, so it's understandable that you want to quiet it down.
