69 400 4sp
all original from intake to clutch fan ect
I AM running at 200 degrees on the E way and a bit more in town
things I have done
3 core radiator has been re cored
185 thermostat is new and working - antifreeze moves when temp hits 185
I have a clutch fan and i installed a 1inch spacer it sits in the fan a little more than 50% inside the shroud
timing is correct not ping or knocking car runs very well
It climbs to 230 degrees when shut off ( that might be normal ?)
so question is
: is 200-210 too hot ?
and any ideas on what can be done to cool it down
I may run a heat gun to test the gauge accuracy

First off, that 185 degree t-stat once opened, will never close again until cool down.

Those temps are better than most running around town or on the freeway.

Just make sure all the seals around the radiator are present, most of these will go missing over the years. Also, if you don't have the core support to bumper support plates (came on 400's and all w/A/C) get a set.

Thanks ill try to find
core support to bumper support plates I do not have them
So i suppose 200 degrees is not too hot ?
I dont thing it boils till 230 ?

230 degrees and you can start worrying.

Most new cars don't have the radiator fans kick on until the temp is in the low 200's, but that's more for emissions than anything else.

I have an idiot light in my 68 and it's rumored that it does not trigger until 242 degrees. I think I may have read it somewhere.

I too would think 200F is good.

Interestingly, I have never found any ideal/target operating temperature for my '68 in any of the documentation.

They do mention a few temps in devices that help control or monitor temperature.

- The stock thermostat was 190F (AMA Specs and both manuals) and should start to open +- 7F (Diagnosis Manual) or +- 7F for used thermostat /187F to 193F for a new one(Service Manual)

- 190F Thermostat should be fully open 25F above it's rated temp. (Diagnosis Manual) or 222F (Service Manual)

- TVS will operate at idle temps above 230F to advance timing and reduce temps. (Diagnosis Manual)

- Using the correct 15 lb cap for pressurization boiling occurs in the correct coolant at 258F at sea level. (Diagnosis Manual)

- The temp idiot light does not illuminate until 248F +-20F. (Diagnosis Manual)

I only have an idiot light and have only seen the light after a thermostat failure and a sending unit failure in 52 years (and perhaps it's first water pump failure in the early 70's - I can't remember). I have occasionally turned on my heater to help the radiator when caught in stopped traffic in extreme summer temperatures as a precaution.

I have read that Pontiac purposely designed the Firebird to run relatively hot (200 to 230) to promote complete combustion. I have a '68. Like you, I am looking for ways to allow the engine to run cooler. (my 2011 Camaro runs at 204, even when the outside temp is 95 degress) I have read that the high temps are not good for the head gaskets and don't want my coolant and oil mixing. I have found plenty of advice for 67 and 68s, but not sure if it applies to 69s. As an example, its recommended that the coolant be mixed 33% antifreeze/ 67% water. The water pump diverter plates require some adjustment to improve flow, but again, I think the 69 water pump may be different. Sorry I am not much help, other than to calm your concerns about running hot.