Years ago someone told me a drop base air cleaner could cause vapor lock because engine heat would be trapped around the carburetor. Anyone running a drop base air cleaner have problems with vapor lock?
Heated fuel causes it to vaporize. That's what causes vapor lock, the fuel boils inside the carburetor fuel bowl. Elevated coolant temperatures and carburetor pre heating via the exhaust crossover can make it worse. The factory designed a fuel pump vapor return line to route hot fuel and vapor back to the tank in cars with a higher tendency for vapor lock. A drop base has nothing to do with that. I have been running one for may years. The stock air cleaner was designed to pre heat air to help fuel vaporization in cold weather. The under hood air will be hot as well especially in the summer time temperatures.
