<VV> Spark Delay Valve - yay or nay?

[Michael Kovacs]

I never heard of a spark delay valve! I'd like some info on it. Who can find this gadget in any of the Chevy parts books? 

Steven <steven at sashimi.org> wrote:   I noticed a little valve in the vacuum advance hose on my 140PG car which I 
learned is a spark delay valve (SDV), installed on cars with A.I.R. polution 
control systems.......

MIKE KOVACS