fumes?????

You have a leak somewhere. Check carefully everything from the carb to the fuel tank. The hood scoop needs to be sealed to the carb. If not, it will blow air back. Do you have anything in the firewall that is not sealed? The doors have a piece to seal the inside of the door to the engine and wheel wells. My problem was my poly fuel cell that allows fumes to escape with no leaks. A metal fuel cell cured the problem. After careful examination, it usually comes down to something simple.