I recently installed a new RPM performer manifold and 670 Holley Street Avenger carb. #s 6, 7 & 8 cylinders are running very hot as evidenced by discoloration of my ceramic coated headers. These pipes have actually looked red in the top 3 - 4 inches where they bolt to the head. Timing is 10 degrees advanced with no vacuum advance. I cant see the carb being lean or more than 3 cylinders would be affected I would think. The timing cover and damper were reinstalled in original position. I have not changed anything else. Water temp is 195 with gauge probe in intake manifold. Any ideas at all whats happening? I never had any problems before this upgrade.