Starting troubles/carb spacer ???

I'm betting on vapor lock. The fuel in your line gets hot enough to evaporate and starve the carb. Turning the car over long enough refills the line and float bowl. Make sure that your fuel line before and after the pump doesn't run so close to the exhaust manifold (or any other heat source) that it can get real warm while sitting after shutdown.

Some people have installed electric pumps to pressurise the system for a minute before starting, but that shouldn't be necessary unless you have a radical set of headers increasing the under hood temperatures.