Sounds like your going after 2 possible causes without certainty of which one it is. If you remove the corkscrew and just try to rotate the top chute by hand, does is it move smoothly, or does it catch at a certain spot. If it is smooth and easy moving, then I would look more into corkscrew adjustment. I looked up the 353 blower parts diagram, what spacers did you add, I don't see any. Some pictures of the area would help us.
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Bill