OOOK.
what is so cool abut the HEMI are a few things:
- first, as some one said, the Hemispherical combustion chambers that allowed for maximum efficiency of compression and allowed power to climb to the engine faster than a normal, standard head engine, because the design permitted a boost in cubic inches (yeah, I know there were bigger engines, but HEMI efficiency + big cubes = monster

) and, combined with the boost of the fual/air mixture into the engine, provided a much quicker reaction of the pistons, resulting in more power/acceleration/torque/speed.
- its torque. as the HEMI head provided so quick burning of the fuel and all of the above, torque was available in a broader band than other V8s (it was like... almost 600 rpm... in that day, it was a lot) so it was quicker on the launches.
- its appearance! it had the plugs for the sparkplugs directly in the valve cover, so the cables came and attached directly into it. this looks very cool and intimidating, because along the look came the... you know, "gawd, the dude has a hemi"
- its sounds: yeah, it was louder and cooler than most V8s.
well, that is a fan thing for sure, but it does gives you goosebumps. anyaway, its high efficinecy burning capacity made the hemi the engine to beat in the muscle car wars of the 60s. it was real fast and could be hopped up easily, but not cheap -_- it was a high cost engine, intended for really high perf applications.
Cano
hey, those links Punk Rock posted are very cool. skip all this and go see them.