With my personal experiences, i always ran a 180 in a carb'd engine, they seemed to run fine with them, i liked them, didn't like my engines running that warm to begin with, no problems with it.
Now that i have TBI, i had run a 195 for the past several years, and just recently switched to a 180 in a probable wasted attempt to help the motor last alittle longer by running alittle cooler, it has 227k on it, with no major repairs, just keep the oil changed and maintained.
But it seems even with the computer controlled stuff, and a 180, it still runs just fine, here in Arizona though, with the 180, it still reaches the 195-200 mark pretty easy.
edit,,just re-read your post and saw you live here in AZ as well,,,definately run at least a 180, i did a long time ago try running a 160 out here, and as for me, it ran too hot in the vehicle i had it in. A buddy of mine runs a 180 on the advise from me, and he is pretty happy with his engines temps,,,at least now after he fixed his temp gauge
