The needle would go full over on long freeway grades, although it never boiled over. On really hot days over 100F, needle would be at the high end even on a level freeway.

That was with the stupid anti-performance motor I'd built back then -- I think it put as much energy into the radiator as into making the wheels go around -- but the stock radiator didn't have trouble dealing with it until it started leaking, which is why I had it recored.

The stock cooling system should have no trouble with a well-tuned stock motor, or a well-engineered performance motor. I'm still using the bogus radiator in our 122 with an unmolested B20E running DCOEs, and it's adequate. The 1800 has the original radiator, and it has no trouble keeping the MPPE cool, even with no fan at all. The temp does creep if the car isn't moving at all and it's hot out, but it takes a good 10-15 minutes of that before the electric fan kicks on and cools things right back down.