Chevrolet: thermostat for 305 V8, smog inspections, engine performance

Question
My engine is in a 1983 Firebird BUT it is a basic question  and I hope you can give me some insight.
I just bought this car and have had it tuned up to exceed the Smog Inspections standards here in CA.
But the engine runs at around 210-220 degrees (which I gather is normal).... but that makes me nervous.  If I drop the thermostat to a 190 degree unit, how will this affect engine performance and longevity?
Many thanks,
Skip

Answer
HI SKIP;
        OK to be short I will tell you
Change the thermastadt to the 190 and if anything it should add life to the engine as it will run cooler , and last longer in normal use. it will hurt nothing at all.
I use to remove the thermastadts in (ALL) of my street hot rods and in some of the chevy v8s that I had , the only thing in the cold winter months I had to run the car to warm up in the mornings. than I would put in a 180 or 190 thermastadt if it got too cold out and re-move it again in the summer.. so do not worry it will be fine .
OK
BIGW45