My 55 Crown has dual exhaust coming out the rear of the car, just like every other vehicle I had with pipes exiting the rear the exhaust fumes roll back into the interior from turbulence or something? Can I maybe just put down spouts on or do I have to re-rout the pipes to exit behind rear wheels? Anybody else ever had this issue? Thanks.
 

My '55 Merc does the same at low speeds, sometimes bad enough to make my eyes water. I suspect turndowns came into being to address the issue but I've never tried them. Deflectors may also work. If you try either let us know the result.

Make a check of your trunk lid seal. Your vent for the gas tank is under the lip of the lid if it is like my 56 Ford. I had a lot of fumes coming into my car from a poor seal of the lid.

56 VIC  Gene Stoehr Sr.

Same thing on my wagon. I've been thinking about having them moved to behind the wheels.

Durham Missouri

I have rear exhaust with downturns on my 55 272 with dual.  Never noticed this problem, so maybe that's the key.

Wagons should never have the exhaust out the back, side exit. My pinto wagon and suburban have side exit.

  Dennis in Lititz PA

Stockers all exited at the back under or in the bumper and mine now and back when we had them new I never smelled and engine exhaust even in our convertable with the top down or rear window unzipped. I cruise with all the windows down in my Vic and smell nothing. In my opinion I think you have an over rich problem. My gas tank vent comes thru a rubber grommet behind the gas filler pull down on its sucks in when running as your using fuel; it should never smell raw fuel when running only when parked.

56 Vic, B'Ville 200 MPH Club Member, So Cal.

That's all it took, no fumes in car now. Yes stockers did exit out the rear but they all had down turns on them, the 56 came out the rear bumper but it was pretty far to the outside of car- all I know is this worked on my car. Thanks.

Our new 55 Sunliner stock dual exhaust exited out the back just inside the bumper guards and did NOT turn down. The actually had a 60-70* slice cut with the last half inch or so cut square. I remember the distinctly as this was the first car we had with duals and I was 11 already reading Hot Rod Mag. After a month or so dad rolled some stainless steel and made some straight tips. I never liked them because I could never get them to be as shiney as chrome ones.
It's funny but when I see restored 55's none ever have the slanted stock pipes like I remember. However Ford did sell clamp on tips over the counter that looked like sea shells to me.

56 Vic, B'Ville 200 MPH Club Member, So Cal.