Got my car on the road and out to some shows and cruises.

Per the advice from this forum I stuck with the stock copper 4 row radiator instead of going aluminum. I'm hoping this wasnt a mistake as the car runs very warm on just 80 degree night. Not trusting the stock gauges I have an after market temp gauge which I would glance down at as it was pushing 230 degrees. Is this a reasonable temp. People say these cars run hot but 230? When driving on open road with wind being pushed through its more like 200 degrees.

The other thing I noticed the hotter it ran the more the throttle seemed to run higher, almost made the pedal feel as if it had a sticking feel. Would run at about 1800 RPMS until I revved it up over 3000 RPM then it would drop back down to 900 RPM but only until I gave it more throttle and it would stick back over 1800 again. Is this something engine compartment heat may cause? I didnt have this issue on cooler runnings.

Do you have all the filler panels on top and bottom installed? What kind of fan do you have (pics pls). 50% water to coolant? Coolant overflow tank? Water tmp sensor in the water stream? Auto or Std tranny? Your throttle cable springs maybe weak or your missing one or something is sticky. Black is a magnet to heat. Need lots of fan at idle. Try flex fan.

The sticky throttle could be the cable needs lube, or the throttle shaft bushings need a blast of penetrant. Do you have an inner and outer spring? It's a good idea to have two throttle return springs, one mounted rearward and one forward of the carburetor. Makes for positive closing and helps keep the throttle shaft from wearing on one side.

Lots of things can cause too much heat.

Here are 3.

(1) Too much clearance between the water pump impeller fins & divider plate.

(2) Ignition timing too low. A good vac advance, that will add the correct amount of advance at idle & cruise rpm, can reduce temp.

(3) Fan not pulling enuff air, for some reason. There are some 6 & 7 blade fans that are designed to pull more air. If a clutch fan, their are some HD fan clutches that will make the fan pull more air. Many say that the fan blades should be partially in & partially out of the shroud.

Assuming that your rad is flowing enuff coolant, & that your thermostat is working correctly. Some say that an alum rad, with at least 2 rows of at least 1" wide tubes will cool better than a stock type 4-row, which has smaller tubes. Some disagree. Some also recommend drilling some small bypass holes in the thermostat. Most recommend a 180° thermo. I always used a 160°, or, in high air temps, just a gutted thermo.

The car does have all the radiator filler panels installed.

the coolant I bought was a premixed blend

I am using the stock 5 blade fan, I feel if this didnt cool it back in the 60's they would have redesigned it.

I do have two throttle springs, but one is not pulling forward? Do you have a picture how that would work?

Not sure which theromostat is in there, doesnt seem to matter to me though because if its 230 degrees it must be open what would the difference between using 160 or 190?

After doing some research, it appears the pontiac 400 produced the most power running at 230

Have a look at this thread: https://firstgenfirebird.org/forums...gus68+%2Bflex&Search=true#Post269319

Correct, thermostats are for cars that need heat to defrost their windows at startup ... no performance requirements. I drive with no thermostat.
WHEN your thermostat gets stuck closed your car will overheat.

The filler panels will help direct more air thru your radiator when idling therefore cooling it more. You have an A/C car? You need a fast Idle Solenoid Switch for Air Conditioning models. This is used on all Round Ports and AC models. This carburetor Fast Idle Solenoid is used to keep car running when cold.

Oldskool has some good points.
Timing is one that gets argued on this forum quite a bit, especially where to put the vacuum advance hose. If the initial advance is set too low and the vacuum advance is attached to the stepped port on the carburetor, the fuel air charge may be still burning as it's going out the exhaust port. That can result in a lot of heat transfer into the heads and the coolant, not to mention burned valves. Placing the vacuum advance hose onto the manifold vacuum port will result in a higher timing at idle and more of the fuel air charge will be burned before it leaves the cylinder. More timing will result in a higher rpm allowing you to turn down the idle speed screw and adjust the mixture for a more fuel efficient idle. The vacuum advance was always on the manifold vacuum port until they came up with the smog stuff, then they needed more heat in the exhaust to burn the pollutants. They moved the vacuum advance to the stepped port and opened the throttle to keep them running at idle. Of course that caused run-on, dieseling, so they had to install the idle step up solenoid. The solenoid allowed the throttle to be closed at shut down but opened further when the engine was started.

The water pump clearance is another good point, mine had way too much but a bit of tapping with a small ball-pein hammer fixed it.

I'm sure you put a new thermostat in when you rebuilt it but it could be defective right out of the box, been there. I always use a 160 degree, I know all the arguments about higher temps resulting in more energy but I feel better having my water temp reasonable idling at a red light when the outside air temperature is 100+F. A 160 degree thermostat starts to open at 160 degrees, may not be fully open until 180, at least that's what mine did when I tested it. 230F at a red light would make me sweat way more than the 185F I have now.

That's just my opinion, I'm not an expert.

Sorry I do not have a pic of two on a quadrajet, I'm running a Quick Fuel and an Edelbrock on mine. You just want the force of the springs to equal out the wear on the shaft and the shaft bore. A lot of air leaks are due to excessive play in the throttle shaft bore. A spring pulling the throttle closed from the front and another pulling it closed from the rear help even out the wear. I have a couple of diagrams I'll add, not the two spring deal, but will give you an idea of what i'm trying to say. You can have a spring pulling the opposite way of the throttle cable but at idle it's just the spring that's pulling in one direction.

I’m in agreement with oldskool and bluebird428 on the thermostat temp. I always use a 160 degree thermostat and like the temp under 180. My current engine is a .030 over 400 with TRWs replacement for factory flat tops, mild street/strip cam and 670 heads. Of course I have to mix my fuel at that compression but I have no overheating problem. I run a stock distributor (vacuum adv hose to manifold) and stock solid HO fan and shroud (which moves a ton of air) with the correct factory fan spacer behind a factory 3 core rad. The engine runs very strong if it has enough advance. If the temp gets much past 180 I can’t run the advance it needs to run it’s best.
Granted it’s a 4 spd car with no air, but I don’t know why so many feel you need the high temp like a SBC. All my many Pontiac engines over the years from PHX to Sacramento have been happy with 160 thermos. Only exception was when something was wrong like the plate or seals in the water pump being corroded.

ok with the exception of using defroster why even use a theromostat at all?

My car in a non A/C 4sp car.

The extra spring, thats interesting, so it needs enough tension to pull throttle cable back but not enough to actually engage the accelerator. would like to see pic of that on quadrajet

Bingo! Exactly, just what the hell bother with it in the summer.

The small spring holds the throttle arm tight against carb body.
Place small spring in throttle arm and the other in one of
The holes such that the arm stays tight to stop.
Big spring same thing except it attaches to secondary
Throttle arm. So it does not stretch until you
Open secondaries. Hard for me to explain but I don’t have avail.

Your carburetor throttle shaft could be binding at the 1800 rpm range or maybe the cable is sticking on the outer sleeve, when you Blip the pedal the throttle returns to idle faster and gets bast the bind.

Check the fast idle cam to make sure that is not hanging up. Make sure the secondaries are closing all the way, make sure the secondary spring on the shaft is connected correctly. Check the choke linkage isn't interfering. Try loosening the carburetor mounting nuts, give the carb a little shake and retighten, sometimes if they are not tightened evenly or are over torqued they can cause a bind. Disconnect the linkages from the throttle and rotate it to feel for a bind in the shaft. Maybe disconnect the accelerator pump while you are checking everything out so you don't flood the thing. If the throttle snaps back with the cable disconnected but doesn't with it connected there may be a binding in the cable.

The two spring idea is to keep the throttle shaft bore from wearing, don't just add another spring to solve you sticking throttle problem, fix that then add the second spring.

I've seen the throttle shafts bent, but yours is most likely something simple like the cable or interference from some of the other linkage.

Just a few ideas of what I'd look at.