First off what cam are you running. Second what is your initial timing? Third and most importantly did you use a NEW valley pan? I did a cam change on a motor with less than 500 miles on it and reused the old the valley pan. after changing everything out 2-3 times I finally pulled the intake and sure enough it was sucking air and oil out of the valley area. Funny thing was it didn't run like it had a vacuum leak and the plugs never showed oil consumption but after I changed the pan it stopped overheating.