todays hemi gets the air in and out of the engine more efficiently.
todays gasoline hemi engines in production vehicles dont get horsepower
by high compression ratios like in the 1960's , we just dont have the
pump gas for it. todays engines get more power thru volumetric
efficiency .getting the air in and out in a better way,many with hemi
combustion chamber, and of course computer controlls on the engine. most
of todays engines use exhuast manifolds that are made like the headers
racers use, to increase volumetric efficiency.

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