What you can do is grab some old cats, and flange joint them up to the area past the H pipe.

With a proper air cleaner, it will sound much like this converted to dual seperates...

https://www.youtube.com/watch?v=2kmkYUJNH_g


Basically, your trying to reduce flow pulses without hurting average gas speed. In scientific terms, you are attemting to reduce peak sound pressure by making the gas flow more lamina, and less urbulent. Adding a honeycomb substrate polarises air flow to a more uniform, linear direction, without hurting back pressure.


When car engineers measure peak sound on the way to 60 mph, and at 60 mph constant, they pick the exhasut that shows the lowest increase in sound, but that still has the least backpressure. Cataysts do this as a consequnce of the catalystic substrate woven into the pipe. It does the best job of reducing emissons and muffling sound peaks.


For instance, the 1982 5.0 HO 2-bbl Capri and Mustang only had a primary catalyst on the passenger side, and one catayst under the transmission. No muffler was required. The cats did the fume mop up, emissions compliance, and created the best sounding carb smog engine ever.