Spider backfires with clutch in.

[Rodosta@domain.elided]

Hello all,

I am noticing a slight backfire when shifting, as soon as the clutch is 
pressed in.  I'm not sure if converting my 86 exhaust to the older free 
flowing type has reduced back pressure enough to make this more noticeable, 
or if it has always been there.  The car runs great, and all of the ignition 
components are new.  What should I look for to solve this problem?

Thanks in advance

Rick
Eugene  OR
86 Veloce
91 164L 

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