Back to Main
Early
Hemi
426
Hemi
MOPAR
ad's
MOPAR in
NASCAR
Links
******
Make your own free website on Tripod.com
THE EARLY HEMI !





History

The Chrysler, Dodge and DeSoto hemi engines owe their existance to the simple fact that the automobiles they powered were very, very heavy! As the demand for larger and more luxurious cars increased the designers were often at odds with the engineers over power to weight ratios. Its a simple matter of physics that as weight increases performance goes down. Customers wanted the "best of both worlds" so the engine department of the Chrysler Corporation had a new challenge to meet.

The logical way to increase performance is to raise the compression ratio and make the engine "breathe" better by increasing the ammount of air and fuel it can "inhale". The only problem was by raising compression ratios, you increase the chance of detonation or "pinging". This can be very detrimental to the life of a engine.

The solution the engineers came up with was not a new idea. In fact it was a old one. Hemispherical combustion chambers. The reason it was not utilized in mass production earlier was the technology did not exist before to produce such a complex casting as the "hemi" head required. This type of combustion chamber design is like half of a sphere with a valve on either side. This allows for greater thermal and volumetric efficiency. In other words, it lets a greater amount of air and fuel into and out of the cylinder. With this design the engineers were able to utilize bigger camshaft profiles thus increasing horse power with out having to increase compression ratios.


The Engines

Chrysler as well as Dodge and DeSoto produced hemi engines. Plymouth was left out of this program as it was the "lower end" of the cost scale. Here's a breakdown of Hemi engine sizes and performance figures:
only the highest performance versions of each engine type are listed...lower performance versions of each were available.

Chrysler FIREPOWER
year cu in disp. horsepower
1951 331 180
1957 354 300
1958 392 390


Dodge RED RAM
< /tr>
year cu in disp. horsepower
1953 241 140
1955 270 195
1956 315 260
1957325310


DeSoto FIREDOME
year cu in disp. horsepower
1952 276160
1955 291200
1957 330255
1957 341292
1957 345345

These engines were NOT designed for all out performance. They were intended to propell very large and heavy automobiles. They did this quite well, but, their REAL place in history was yet to be played out. The era of the fuel dragster would etch the name HEMI in the history books forever!


NEXT UP...THE FUN STUFF!!!

ON TO THE FUEL DRAGSTERS