Originally Posted by rockbatty
help an old dude out. guys I'm 56 an built my share of sbc's but have never experienced a cooling problem such as this one. it's a 9.50 to one 350, .465 lift hyd, team G intake, 650 holley; cam installed at 3 degree advance new MSD street fire HEI with all timing dead on the money with manifold vacuum advance; 3800 stall converter W/remote cooler, turbo 400, to narrowed 9" running 3;50 street gears. has largest alum Jegs radiator that will fit, w/shroud & big elect. fan, flowkooler pump, stewart high flow 160 degree therm w/bypass holes running no heater hoses but do have intake port to pump port hooked together w/molded hose, all other hoses new w/wire inserts, my first experience running alum heads, they are pro lightening heads W/felpro gaskets. car runs extremely well, but after only a short cruise runs at 205 degree w/sensor in the head, also have tryed different gauges.
I'm a bit perplexed,,, any ideas out there, any suggestions appreciated and thanks for reading this long *** thread.
I would find 205 against a 160 thermostat to be more temp than I'd expect.
Most cooling systems run 10 to 15 degrees above the thermostat's open temp, so I'd expect yours to be more like 170 to 180 on the high side. I would agree with the consensus writing here that 205 isn't harmful, but it's greater than I would expect with the thermostat you have.
Consider you've changed the heads to aluminum which transfers heat faster than iron, you'd actually find a hotter thermostat reduces the delta T between the coolant and the head which increases the efficiency of the combustion chamber.
I also see you've put on a Flowcooler pump, which causes the question of whether you changed the pulley ratio as well.
Then there's that 3800 RPM stall converter which leads to why (I mean I think I know but tell it to me anyway). High stall converters can dump a lot of heat, if the tranny fluid is exchanging temperature with the radiator coolant, this could be a contributor.
Then comes the question as to the vehicle type, weight, and gearing.