This is one of the biggest reasons I switched from a carb to fuel injection. My exhaust dump just in front of the rear tires on both sides. It was terrible smelling with the carb. I used a wide band o2 sensor and tried to get the AFR tuned correctly. The problem I ran into is that the carb I had was impossible to get a decent AFR tune across the whole rpm range. So there was always some unburnt fuel at certain rpm ranges when I drove it. The fuel injection has solved all of it. I thought perhaps I would still smell something with the doors and top off, but I've driven the last month with it this way and there is absolutely no smell.