ProComp/Speedmaster aluminum heads

Back on track here: Graham noticed when he was pulling vacuum to check the valve sealing that there was a couple of Pin holes where the CNC machine nicked the valve cover bolt boss. The bolt does seal it up. Just a FYI. Kim

I heard that as well, and noticed the same thing on my heads when I checked them over. Easily dealt with by using some sealant on the threads, especially if you use studs instead.