Shave the intake manifold to correct angle as well or forever have sealing trouble.Yep.03, we would use a Serdi guide and seat machine to put in hardened seats for the 202 intakes valves. The angle plugs aim the spark towards the intake for better firing. That Serdi machine puts a sleek 5-angle seat for the valve. Shave off 0.030" from the surface with a rotary broach for added compression. Port, polish and BAM! you are set...