MRGTX

That's possibly true...but that's never the approach I'd take with a car, especially not a high performance car with an 11:1 V8 engine.

Excess cooling capacity and "head room" in the system provides reliability and longevity...and it allows you to sit in a traffic jam on a summer day with the AC on.

Yep...it might be ok...but I'd also not choose to run less oil to save money/weight even if the car would technically be ok with 7qts.

Horspla

Out of curiosity, are you suggesting that there is a difference in how a heat exchanger works depending on its application, cooling and cooled media?

I also agree there should be plenty of headroom in the Mustangs cooling system for it to afford to have the radiator painted. As somebody else pointed out, it’s not the radiator that he’s seeing, it’s the AC condenser…that may not have as much headroom without noticing a loss of efficiency.

John