Why I ask this question, is because my '55 265 engine is under cooled if there is such a thing. It takes forever, even on the hottest July day, to reach operating temperature which is I believe 165 degrees. Sometimes, it stays in the 160 degree range. I contributed to this issue. When I first bought the car 4 years ago, trying to be proactive and avoid any future running hot/overheating issues, I replace the original radiator and 4 blade fan. I installed a 2 row 1 1/8" aluminum radiator and 6 blade fan. Big mistake. I should have run the car first to see what temperature it would go to, but I didn't. Now I have this issue. I should be happy that it doesn't run hot or overheat, but my concern is it not getting hot enough to burn off impurities in the oil?? At least that's what I read. I'm assuming I have a 165 degree thermostat and I'm thinking about putting in a 180 degree one. I don't want to put the old radiator and fan back on. The old radiator could have been a recore?? Not really sure?? That's why I'm soliciting ideas on how to proceed next. I want it to operate correctly, Carmine.