[Gaz64]

Any form of insulating spacer makes some difference, but the carbs will still get heated from the engine and exhaust.
The inlet manifold heat still conducts to the carb base via the studs/nuts.

I have found mounting the carbs in a heat shielded box and letting the outside filtered air to run around the bottom of the carbs prior to the top keeps them cool.

Fully isolated insulators with studs top and bottom isolate the carbs better, but near impossible to fit on a V8.