hemi is short for the nickname given to the type of engine that C-P-D-D (Chrysler-Plymouth-Dodge-Desoto) used starting back in the 50's. It was a V-8 and used in the Imperial line made in the 50's,60's, & 70's. The engine was proven to be a powerful horsepower producer.
More specifically the term refers to the Hemispherical Combustion Chamber in those engines and a special cylinder head that created that type combustion chamber. It also allowed a unique valve placement arrangement and strategically placed the spark plug in the top of the cylinder head for improved combustion of the air/fuel mixture.
These engines were produced in the following cubic inch displacement sizes 354,392,426.
My father had a 1956 Dodge Royal which had a 315 semi-hemi in it the plugs were offset in the combustion chamber. I also purchased a 1957 Imperial which had the 392 Hemi in it. I purchased that car for the engine only and re-sold the engine for a 300 % profit margin. (and you guys thought I only used % for bankroll management :tongue
) I sold that hemi to a tractor puller as these engines were popular for that competition.
Of course a lot of Super Stock, Modified, Pro Gas, Funny Car and Top Fuel drag racers also used the hemi.
There you have it njsf, a complete nutshell overview on the hemi engine and now you will come to appreciate the hemi heritage that is being handed on to a whole new generation of hemi lovers.
I now decree upon you an associates degree in hemi information free of charge and you got it from the PHD of useless auto information hemi-self,..... Dr Auto Parts aka Geno
Don't forget the first four letters of General Motors is Gene.
(as foghorn leghorn would say "It's a joke, son" )