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1.
Term used to describe 2-stroke Detroit Diesel engines (i.e. 6-71) known for their distinctive tones and volume. Detroit Diesel was a division of General Motors, hence "Jimmy"
Trucker #1- "Dang ol' sum bitch's trucks louder than sin!"
Trucker #2- "Boy howdy! I reckon he's got a screaming jimmy in that pig"
by Chet McPherson II June 17, 2011