>>>Question...is there any good reason why I should not do this, and  keep
the .25" spacer??

Angier,

Although I don't know the specifics of Lycoming engines, I do know that
automotive racing engines will sometimes use spacers between the carb and
the intake manifold to "increase plenum volume" (which, depending on how the
spacers is sized, is supposed increase either top end power or low and
mid-range throttle response), "smooth the airflow transition between the
carb and the intake manifold", and for phenolic spacers, "reduce heat
transfer between the manifold and the carb".  These descriptions are from
the descriptions of various carb spacers in the Summit Racing catalog.  The
engines in the car that I raced is port fuel injected, so I have no idea if
or how well these things work.  I suspect the 90 deg. elbow will eliminate
the need for the spacer, but if you find you're consistently getting your
wings blown off by RV's.... ;-)

Gary Fitzgerald
LNC2 standard build ~65%
Engine: TBD
St. Charles, MO
3380+ hrs of fiberglassing fun and counting