Kevin, I don't like the Stant #11810 because it has a venting pressure relief spring-loaded diaphragm. Both the locking and non-locking OEM caps do not vent at all. I bought the same Stant #11810. Without taking it out of the package, I pressure tested the diaphragm using air. I found that it leaked at pressures well below 1 lbs psi. The pressure was so low that I quickly ruled it out as an acceptable cross-reference considering that the OEM caps (particularly the non-locking variety) can hold several lbs psi. If any vapors are going to escape from the tank, then you want them venting through the vapor recovery system rather than wasted through the cap. If you keep smelling fuel, then don't rule out that it could be coming from your new #11810. Before I modified by Stant #11623, it had the SAME venting spring loaded diaphragm as your #11810. It caused my car to stink like gas really bad -- even to the point of making me sick. On short trips or with a mostly full tank of gas, it didn't bother me. But when the tank was less than half full, the fuel in the tank would heat up from being circulated through the fuel distributor and also from having heat from the radiator fans blowing on the tank. At lower fuel temperatures, there won't be enough pressure to vent through that cap. But once the fuel gets hot enough, then you will have problems. The hot vapors come up through the cap, cool and then since they are heavy, they drop right into the intake of the a/c system stinking your car's interior up. I suggest you plug the vent hole on that cap or buy an OEM cap from one of the vendors. A local friend bought a new cap from PJ Grady. It is non-locking, totally sealing and has a number stamped in it that indicates it was manufactured in the early '80s, so we think it is new old stock. It has a black plastic cap with a handle/ridge in the center. Keep us posted about how things work out for you. Walt Tampa, FL -----Original Message----- From: Kevin Creason <dmc4687@xxxx> >Walt- I also got a Stant, but it is #11810; it's not fancy but it is a pressurized cap and fits snug and needs to jerry-rigging.