Does anyone know how to quiet a'76 FE 390? I'm used to it but would like it a lot quieter. Want to do this with little funds. I can run it without muffler and sound hardly changes.

 

Those old cast exhaust manifolds like to crack and split, exhaust donuts leaked, exhaust manifold gaskets blow out, pipes/flanges rot out. If running without a muff isn't a lot louder, I'd be guessing you have some substantial exhaust leaks.

If you can better pin point any leak areas, would be easeier to make suggestions.

 

As far as I know there are no leaks and I have long tube headers on. I was convinced it would give me more power, turns out I just needed to tweek the fuel and ignition a little. I did however found header was cracked at collector and welded it and did not really make a differance. And no leaks that I know of. 3" exh in and 2 2.5" tailpipes. was that way when I got it. little to no rust on entire exhaust.