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Originally Posted by Power Surge
Also, Ford's 4.6 DOHC (DUAL overhead cam) motor is a hemi. It's a modern version, with 4 vales per cylinder, and a central plug. You could use that for your paper to tie old technology vs new.
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Although the 4.6 DOHC reminds you of a hemi, it is not. I believe the technical term is PENTROOF, but I would have to pull a book to be certain. A hemi head is shaped like a ball (top half) except where the valves are flat. That is to say there are no flat surfaces on a hemi head. The 4.6 DOHC has all flat surfaces (except the curve to match the cylinder wall). The valves are not nearly as canted as a hemi either. However the flow is excellent, and from an emissions/performance point of view it is superior to the hemi in many ways.