question on phenolic spacers

Running it on the dyno is just about the only way to see how it likes it.
Having said that, most big HP engines run spacers in the dyno competitions.
Definately run some kind of heat insulator spacer with an Eddy carb. They are known for heat/fuel issues. Either way your on the right path for cooling the carb/fuel.
I run a Edelbrock #9266 heat insulator with my Eddy carb and Eddy RPM intake. Works well.