Exhaust Sound

[shelbydoug]

I haven't had to think about this in a long time but I believe that the stock exhaust is essentially tuned to the camshaft the car was originally built with.

Virtually any aftermarket cam is going to be more aggressive and the difference you are going to hear through the exhaust.

I don't know how to keep that burbling sound that you get with the 69 Shelby when you back off of the accelerator? I don't think that you can.

There are inserts that are made to slide into mufflers BUT they need length to have some effect. They were originally intended for Corvettes with factory sidepipes, then adapted to the Cobra sidepipes. They just "take the edge" off of the noise. Officially the number given to me is that they drop the sound by 5 decibels.



I remember when I first bought my 68 GT350 in 1972, it needed a new exhaust system so I bought a complete original Ford system which included the in line resonators.

At the same time I rebuilt the engine and installed a Crower 280 hydraulic cam. The cam made such a drastic change to the sound of the exhaust, it set me off on a exhaust project beyond the stock.

It eventually went to headers, 2-1/2" od pipes with "Corvair Turbo" mufflers. Those were eventually replaced with Flomaster mufflers.

No inline resonators. That's about the quietest it is ever going to be. Oh, 82 decibels is what it measures immediately behind the car. 85 when you rev it. Maybe it's 85 at idle? I haven't checked that recently.

The cross flow muffler is essentially an rpm limiter set at about 6,000rpm, i.e, a "cork" in the system . So depending on what you want to do with the car is what you should do with the exhaust.

I seem to remember difficulty with keeping the main pipes connected to the transverse muffler. They would "blow off".

[FL SAAC]

+ 1 shelbydoug

[427heaven]

Fastback- There are 2 types of CAR guys, Original sounding and looking types that have to be correct in all aspects, and the others that want that Sound and performance from their cars. Where the waters get a little muddy on this site is to help people with their immediate needs what ever it may be. These cars were meant to go fast and sound great but 50 years ago straight pipes,cherry bombs, turbos were the way to go. Fast forward 50 years and technology comes to the rescue,there are so many GREAT SOUNDING systems you just have to ask around what others are using. A nasty camshaft and and a new set of Flowmasters or Borlas is what most performance or race car guys that are required by their track, are using. They make MANY different sounding sets so ask around you will find what your for. Good Luck!

[69 GT350 Vert]

That's good to know. What cam did you use? I'm rebuilding my engine now and I am considering Comp Cams 268H or something similar.

I used this cam.  Nice lope, but not over the top.
http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=896&sb=2

[Stubee]

NOS 1969 Muffler with original manifolds with reproduction pipes a d resonators.
Enjoy.

[Stubee]

Sorry unsuccessful link.

[69 GT350 Vert]

Stock ford transverse muffler. 
https://youtu.be/wIK8uK-JZFA