Rochester carb question

[gogo34]

Since my Rochester carb needs to have the slot cut out of both the gasket and the phenolic mounting spacer to allow for the Direct Manifold Vacuum Passage to have access to the carb "throat," do I still need to install the intake manifold liner? I don't see how using the liner allows for the vacuum passage to work. The PO had the liner in there with the Rochester carb but that could have been contributing to the crappy performance I experienced when I bought it. Now that I'm halfway through with the manifold rebuild I realized it didn't look right. What's the liner do anyway?

You can see the liner identified by the number 7 on the exploded view of the various manifolds on the RN website.

[Les Parker]

Manifold insert

# RNB658 is to align the phenolic block with the inlet manifold. Sort of stops it wobbling about.