Roar in cab after dual exhaust installation.

[Charlie]

Update:

Performed experiment.

I have the tailpipes dumped down right before the rear bumper. I got 2 18" flex pipe repair kits. Put them on the ends of pipes, formed them to point to the rear below bumper.

I can tell it was less drone than without them. I think I can live with this. Now maybe go back and have exhaust pipes extended to go further back under bumper.

 

[Nonstop]

Can there be a leak in the system? Between the smell in the cab and the noise, it is possible they are connected.

 

[Charlie]

Can there be a leak in the system? Between the smell in the cab and the noise, it is possible they are connected.

Nope...What I thought was exhaust smell is probably gas smell but cannot find where it is coming from when at stop sign or light. It has been going on since purchase in 2015. The roar (drone) is from the new dual exhaust w/flowmaster 40's installed recently.

 

[77 K20]

I did vortec heads an small cam, made me stop recommending the pypes violator mufflers and understood why they were removed from a newer GTO.

The vortec heads make a huge difference in sound.

With my stock 400 I had Thrush chambered mufflers installed and dumped before the rear axle. Sounded deep and kinda loud- not annoying- and sounded great. After putting a cam into the 400- sounded even better. Ram horn manifolds- sounded the same.
Then replaced with a 383 with vortec heads... ANNOYING at about 2,200 RPM. Horrible drone and it was like twice as loud at that RPM. Couldn't stand it so swapped out the mufflers for Magnaflow. Now too quiet unless I really get on it.