I wouldn't think so either. It certainly helped power. The oil pressure starts at 60 cold, then drops rapidly. If I rev it, goes to 20. I will do a compression test on it, this the lowest it has been for oil pressure, it may be dying. It may be the condensor blocking air flow, has a few bent fins. Since this compressor wants to leak no matter what, I will probably abandon the A/C, there has to be a more major leak now, charge leaks out as soon as I put it in. Is there rubber side strips along the radiator for deflectors? Maybe missing air flow directors is this cars problem, has never cooled well, the 403 was a nightmare. I do have a 2300 stall as well for the 2004R. If this car isn't going to get 30 mpg, it may as well run 14's and be fun to drive.I like to hear the good. The bad, not so much... Got to get that temp down. If you can get the temp down to a normal 180, you should see a rise in oil pressure, unless it never rises above 15 psi. I would not think that headers, and duals killed the mileage.