Gas Cap

[Carmods@aol.com]

Brian,

 
High gas pressure will cause you carburetor to leak, especially if it is a  
Holley with the externally adjustable float valves. The valve in the cap seems  
to only let air in as the gas is used. Probably on most old Sunbeams, the cap 
 gasket will leak enough to vent the tank. Mine doesn't leak and the  
pressure was building up on hot days so I drilled a very small hole in one of  
the 
smaller diameters of the cap.
 
                                                                              
          John  Logan