[nUcLeArEnVoY]

1979 Trans Am W72 400/4-Speed; stock low-comp 400 with a mild camshaft and true dual exhaust; everything else more-or-less stock. I'm running an 11-bolt Flowkooler clearanced down to 0.050" w/ gasket; Oversized 1.25" 2-Row Cold case radiator; new copper/brass heater core; 160 degree thermostat (balanced sleeve type); all new hoses and lines with anti-collapse spring in lower hose; 15 PSI rad cap as original; stock fan shroud; stock 7-blade 10008888 19" clutch fan; Hayden #2747 heavy duty clutch; shroud sealed to radiator with weatherstripping; all factory baffles and seals in place; stock overdriven AC waterpump pulley; stock HEI with 18 degrees initial timing as per factory spec; vacuum advance metered through the factory modulator valve that supplies partial manifold vacuum to the distributor (around 17 degrees of the full 25 degrees the advance canister supplies), and so I'm making 35 degrees total advance to the distributor at idle. Mechanical advance around 34-35 BTDC by 3500 RPM. Cooling system jackets clean as far as I can tell, since every flush I've done has never revealed dirty coolant - it always comes out green. I use Napa 50/50 pre-mixed conventional green coolant and every couple years as part of a backflush and refill, I throw in a bottle of Rislone Super Coolant additive, cuz why not?

I live in SoFlo, and around town, my car struggles to reach operating temp and I can idle till' the cows come home and the needle will almost never reach that first tick on the temp gauge (which for 2nd gens, I've always interpreted as around 160 degrees), no matter the ambient temp. I can drive around town for an hour and literally grip my hand around the radiator hose and hold it without getting burnt while the car is running.

My temp will creep up to the first tick, maybe a little past it when I'm on the highway sustaining higher RPMs, and that's after roughly 10-15 minutes on the highway. I've never been on the highway long enough to see how high the engine temp will go since I have a driveline vibration above 60 MPH that I need to address, so I usually avoid taking the highway, anyway. I have the factory 3.23 gears, and so in 4th gear on the highway, I'm at around 2250 RPM at 55 MPH, so figure around 2800 RPM at 70 MPH.

The AC, however, will cause my engine temp to spike very quickly. I think something may be wrong with my compressor or AC system, because while it does blow cold air, it taxes the engine a lot and just sitting there idling, I've seen the temp needle creep to halfway between the first tick and 220 tick on the gauge within maybe 8 minutes before I freaked out and shut off the AC. It's been converted to R134A, but only had the lines and compressor replaced with a crappy reman unit, while the condenser and evap are still the originals. I usually drive the car in the evenings, so I don't use the AC.

Overall, I'm pretty happy with the performance of my cooling system for living in SoFlo. Leagues better than when I first got the car, even though even then, it has never overheated. I just wish I could more confidently use the air conditioning, since living in SoFlo without it is oppressive and you need to make a lot of concessions to be able to enjoy the car without it (i.e. driving it only at certain times of the day when it's not as hot out, or depending on what time of the year it is).

I also think that people's standards for how these cooling systems operate are a little high, especially in accordance to the factory specifications as shown in service and owner's manuals. People get awfully paranoid just seeing their car in the 190's-200's, when in reality those are totally normal operating temps which these cars regularly saw when new. So many of these overheating threads may not even be based in actual overheating, but rather, "car not running at a temp that I, the owner, personally like to see it at."