you didn't say if your intake was heated, or not, but, on exhaust-heated intakes, the spacers help prevent carburetor gas perculation, when you turn your engine off.
i have run homemade gaskets on aluminum, multi-carb intakes that were water-heated with no sign of perculation. unheated intakes should not require the thick insulating spacer/gaskets, either.
however, it's been my experience that driveability suffers from an unheated intake.
