Question on changing to a 180 thermostat. Will it effect my fuel economy? A guy at the parts shop said it could change fuel consumption with the engine running at a cooler temp. Is this or does he have a point?

I'll probably switch anyway because my intake plenum cracked last Oct. and that was a pain to deal with.

Mine didn't affect my mileage a bit, and I even drilled bypass holes in it. Thousands of GP'* and Bonnevilles will back this up. Your engine won't run 15 degees cooler as you might expect, but it will run cooler. Keep that trans cooler in mind too.

Great! Thanks for the input. My trans cooler is on the way too