more or less, its a style of cylinder head....like the design of it.......

 

A "HEMI" ,short for hemispherical,refers to the shape of the combustion chamber.The hemispherical shape allows the intake and exhaust valves to be more or less directly in line with the ports of the respective manifold allowing for impressive flow numbers.
And a very impressive look from the outside also!

[IMG]local://upfiles/25247/BCC2D2D8ED2746C8925770F62D700271.jpg[/IMG]

[IMG]local://upfiles/25247/C14788C81447467DA4B14B3EDCBE3747.jpg[/IMG]

 

damn those boss9 motors fill an engine bay dont they.

there is a crazy guy out here with an original 69 like yours in grabber orange (i think thats what the color is called).
he just had the engine rebuilt with a stroker kit...its now out to something like 510. As if he needed some more torque or something. The rest of the car is completely unmolested.

 

A hemi also allows the use of larger valves, but the downside is it also prevents a multi valve configuration.

 

Actually,the 4.6 DOHC and the 5.4 DOHC engines have a modified hemi combustion chamber with 4 valves per cylinder.

 

Modified (modern) hemi combustion chambers although still called "hemis" are not truly hemispherical but pentroof allowing the use of multiple valves.