My 91 RS had factory 305 with all factory water pump, 195* thermostat, 230* fan switch, stock radiator. I swapped to a 350 Carbed and left the 195* thermostat, new stock water pump, and new stock aluminum radiator. Well the car would run around 200-220 all the time but no more. I figured that was to hot so I installed a 200* fan switch and a 160* thermostat. Well now the thing will be running around 180* down the highway and then jump up to about 230* and I pull over and wait for it to cool down. What is up? Is the 160* thermostat letting the coolant flow to long therefore heating it up to much by not letting it cool in the radiator? Any thoughts?

Thanks,
Kevin

 

Sorry about the crappy pic, screwed something up. Call it modern art!

 

hey what kind of thermosat you running i bought the high flow one from summit with the high flow water pump kit and my car is doing the same thing im not sure whats wrong except mine stays at 220 or a little hotter in tiown and sometimes up to 240ish and at night it will normally stay down to 160 i had this same temp thermosat in my old 305 abd it satyed at 160 never got higher. im lost anyinfo would be helpful thanks

 

before with my 305 I used to have similar problems.. it appeared after I had to replace my water pump though.. sometimes the tolerances on those things are a little off..