One vacation a year, my wife and I, and that is the week of Cruisin the Coast. The 421 TriPower in her 65 GTO has quite a few performance enhancements including a roller cam, H-beam rods, custom forged aluminum pistons, etc. So I find antifreeze under the hood in the area of the radiator, but I don't see any source. Ordered the Cold Case radiator overnight delivery. GREAT price and they deducted the cost of regular ground shipping to calculate overnight shipping cost (forum members get free ground shipping). I decided to change the radiator cap and that stopped the leak. So I didn't need overnight shipping after all, and although the leak on the factory radiator was actually the cap, I am very glad I got the Cold Case radiator because we are adding Vintage Air. As for the Roadrunner, the 26" factory radiator has seen better days, and I am adding Vintage Air as well, so I'm happy to have a new Cold Case radiator too. It arrived only 2 days after the one I paid overnight shipping for. Thank you Cold Case for the tech support and for free ground shipping and the generous discount! I'm excited to install both of them and I will be sure to post results.