Beware of one major Hemi-problem, that the rockers sometimes do not line up well and try to push the valvestems away. (Too short, and wrong geometry) This, along with coarse finish on the valvestems can eat the guides after a short while. And the MP alu heads have valvestem clearances same as iron heads, way more than needed on alu heads. When building a Hemi you need special attention to the heads, or you will get an oilburner....