I have a 66 289 coupe that I bought a few years back that was built for 1/4 mile racing. It has a healthy 11.5 to 1 CR 289 and the previous owner put a Holley blue fuel pump on it, a non-bypass Holley 12-803 fuel pressure regulator and a new tank with a different pickup (a 1/2" copper line drilled and soldered into the side of the new tank) that allowed fuel to be drawn from the bottom of the tank via a 1/2 " separate fuel line that was inserted to almost the back of the tank. I installed a Holley 12-803 Bypass fuel pressure regulator and used the stock fuel line as the return that the previous owner left in place and capped off. Doing this made the fuel pump quieter but now after filling the tank with 10 gallons of gas I have this horrible gas smell all throughout the garage. I looked very carefully under the car with the electric fuel pump off and turned on for any leaks or wetting and have found none, just the horrible smell. It is difficult to determine where it is coming from as everything smells and I was wondering if by installing the bypass type regulator I have now "aerated " the fuel via the stock return line and this is why it smells. I have a new gas cap installed and once again, have no leaks or 'wet" fittings. This problem did not exist with the same setup without the return line only after I made this change. Any suggestions? Brian