My 58 Caddy has a overheating problem. As long as I an doing 65 down the highway the temp runs about 180F. If I'm in city driving it will go up to about 190F. The car heats up to operating temp by the time I pull out of the driveway and go 1-2 blocks. If I run the AC I have to be on the highway at 60-65 to hold 185F. If I slow down or get into traffic you can watch the temp go up. I have power flushed the Block, re-cored the radiator, installed a new water pump, changed senders, and tried all the magic liquids they have on the market today. Nothing seems to help. I did drive the car on a AACA tour this summer but was unable to use the AC. Driving up mountains also causes the temp to rise. I want to use this car for tours with the AC on. I'm getting ready to pull the heads to see what I have and the engine if required. Any ideas? Please help.