Does the operating temperture for the engine affect the performance and/or gas mileage? Why do the catologs have three different thermostats listed for the same application?  165, 185, 195. If they advertise a aluminum radiator to run 20-40 degrees cooler, and a specific thermostat is used, say 195, how does it run cooler if the thermostat is the determining factor? What am I missing?

The hotter your engine can run, up to a point, the more efficiently it runs.  The bit about an aluminum radiator running cooler, they are referring to if you have an overheating problem.  The thermostat is the controller of temperature if the cooling system has enough capacity to remove the heat.

Larry

 THANKS, LARRY! I was more than sure of that fact, but was taken in by the advertisement hype.

The aluminuminum raditator will dissipate the heat quicker than a brass raditator. If all you do is swap the raditator, then coolant exiting the rad would be cooler than it would be on the brass rad. The thermostat controls the flow of coolant thru the engine. Changing to a 160* from a 190* thermostat will simply open the thermostat sooner...it will not necessarily lower the operating temp of the engine overall.
Larry is right, too, about engine/fuel efficiency as related to engine temp. Consider that the newer vehicles are designed to run a normal temp of over 200*, whereas a 200* engine temp for an early Shark would be scary!  If my '74 gets over 190*, I'm gettin nervous! My '85 regularly runs around 220* in town, but can go even higher(235* is not unusual) without much of a problem. On both of my later model Caddys, normal engine temps are around 216-220*, all day long. This is done to make the engine more emissions friendly, more than anything...the extra fuel mileage is a bonus.

btw...still diggin into the hood for ya...I still ain't fergot ya!

THANKS,  Joel.  I grew up with a bunch of 195 termos in various cars. The old stand by I guess.

Hey Mark..not to but in but if you find a hood and don't want your old one let me know.
Thanks
Rich

I'm sure Mark would be more than happy to send you his "old" hood if I can find mine to send him....right, Mark?

Adams' Apple2011-01-26 20:41:39

I knew I was biting off more than I could chew here! Just would give me an excuse to drive up north country and visit M&S! I doubt he would trade for some home made peach ice cream..but it still would be fun..
Richyostusota2011-01-26 23:27:17

  10-4, My friend. Don't need an excuse to drive up and kabitz for a spell. Different times we have TRIED to set up a mid-winter food and fun time with the nor-easters in the plastic group, but does not seem to get off the ground. Meeting place for all involved, so distance is somewhat the same creates a problem. Come on up we'll pull some wrenches and tighten a few burrs. Ya, I know, i'm off topic.   Mark     Did you say ICE CREAM!  We are known to make a batch or two ourselves.

Of course if you have an 82 crossfire it needs to run 190 or so if it is ever going to idle correctly.  As soon as I replace mine with the recommended one the idle RPM dropped 250  It still is 200 to high I chasing that ghost.