I'm pretty sure there was an aluminum block version of the 53 series engine, that was used in a piece of military equipment. Don't remember if it was a 4-53 or a 6V53. Much lighter weight and higher RPM than the cast iron types. The 1-71 was used to power refrigeration units on railroad freezer cars.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!