I'm having an overheating problem as well and I put an infrared heat gun on my exhaust pipes just coming out of the heads and I'm getting 675ish on all but #6 is like 550 and # 5 is so hot it don't read (over 800). Now I'm wondering if maybe my stock cast iron intake manifold is warped or cracked somewhere? I'm also going to try tapping and plugging that hole in the WP housing.