My 71 cuda has header and 50's series big block original flowmasters. Thay are great sounding mufflers. Drone is some other problem associated with 40's and muffler placement.
My 85 c10 has headers and dynomx super turbos. They are not quiet as advertised. Mounted under the cabin they have as much resonance as any muffler. They were half the cost.
A friends 350/350 impala has summit turbo mufflers that were $12 a peice and sound fantastic.
