The carburetors on my engine are made by Walbro, these are called diaphragm or pumper type carburetors, they work very well as long as you choose the correct bore size, these carbs require a small pressure pulse to operate the diaphragm, this is usually obtained by fitting a pressure tap in the crankcase, but on my V8 this would not work. I was going to build a small pump driven off the rear of the camshaft. After visiting with a few people about this I decided to use their method.
I used a Purolator electronic fuel pump, this provides a pulsing flow of fuel to the carboretors, make sure you buy the correct model there are several, you want the blue one that puts out very low pressure. These are available at most auto supply stores.
To use this pump you simply connect the input of the pump to your fuel tank and the output or pressure side to the fuel inlet port and the pressure or diaphragm port of the carburetors. The pump and a small 12 volt rechargable battery are hidden under the base of the engine.