Carb spacer

[1] If it is a dual plane intake, use a two hole spacer.
[2] If single plane, use an open spacer.
[3] Problem with thick 'gaskets' or a gasket stack is that they can compress too much, with the carb mounting bolts being overtightened. This can flex the carb base, & cause the t/shafts to bind.
[4] Much better to use a phenolic spacer with a thin gasket top & bottom.