Allstar 9-5/16 inch Center Distance -8 AN Male Inlet Carburetor Fuel Log for 4150 Model Holley Series is designed for 4150 model holley series carburetors. It features a-8an male inlet and has a 9-5/16 inch center distance. The fuel log has 1/2 inch npt and 1/8 inch npt plugs which can be removed when installing a return line or fuel pressure gauge. It is backed by a 90-day limited factory and sold individually.