I was running about that hot this summer in Tucson on a freshly-breaking-in engine. After changing out to a 160* thermostat, it was still hot until I thinned out the coolant ratio. I was running about 70% Prestone, 30% water. I thinned it out to 50/50 or even 40/60 and my temps went down. Now it runs about 180* even in winter [such as it is here].
I/I #4101
'71 GMC Jimmy 350, sm465, np205,3.73 posi.
'68 C/10 Stepside 292 (.030 over) Offy Intake, 500 CFM AFB,Clif headers, sm465, 3.73 posi.
'67 K/10 454 project.
'72 K/5 rolling frame project.
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