Carb spacer - What for?

[landl@ix.netcom.com (LYN MARKMAN )]

77 Midget with 1500 engine and a single Zienith/Stromberg.  There is a 
3/8 in. spacer between the carb and the intake manifold and I just had 
an interest in its function, if any.  It incorporates a small recessed 
area (aprox 1/4 in.) which appears to allow the bypass of air or fuel.  

Went to a great Brit show sponsored by Moss in Solvang, Calif this past 
weekend.  Wife and I really got hooked.  Another show coming on Sep 
24th in the San Fernando Valley.  We'll be there.

Thanks  Lee and Lyn