1966 Barracuda - exhaust smell

I have a 65 and 66 Barracuda, both Formula S cars. I believe the rear end aerodynamics of the early Barracudas are such that the design creates a vacuum sucking exhaust gases onto the lower edge of the trunk lid and even onto the top of the driver side tail light. On any early non restored Formula S cars, look at the driver side bumper chrome and tail light chrome and you can see the caustic effects of exhaust gas. For this reason, I frequently clean these areas on both of my cars out of necessity....the 66 is white and the 65 is silver.

The trunk seal is the most important item in the mix. If it's leaking there will be exhaust gas smell in the cockpit. And as stated in posts, the flow through ventilation flaps must also seal.

One thing not mentioned so far is a possible leak under the upper chrome trunk strips and hinges. (Where the fish or Valiant medallion is located). The hinges and chrome strip came from the factory with foam gaskets to seal them. Check to see if they are present.

I wonder if the 2 barrel 273 with its single downturn tail pipe has the same problem with exhaust gas. My 66 and 67 Chargers have downturn tailpipes exiting a couple of inches forward of the bumper and I see no signs of paint discoloration or exhaust smell.

It would be cool to see wind tunnel tests to determine the air rear flow pattern of these cars. Perhaps a properly positioned deflector would solve the problem.