You are probably thinking of the pesky mammal that squeaks, eats any food that you left out, and is a general annoyance. I’m thinking of the rat motors, built by Chevy in the 1960’s. The rat motor was Chevy’s big-block V-8. They were offered in 396 ci, 402 ci, 427 ci, and 454 ci regular production engines. There were also the special aluminum-block 427 ci, 430 ci, 465 ci, 495 ci, and 510 ci rats, built especially for race cars. Built in factories, they were genetically engineered rats (or at least mechanically engineered!) Now for the interesting part… The name was coined by drag racers and tire-smoking teenagers (NOT me), who called it the rat because it was an outsized companion to the small block “mouse” engines, and the rat’s ability to scare the Chrysler Hemi “elephant” motors. Trivia moment: The Chrysler Hemi was called “the elephant” because it was so heavy! So, inevitably, the Chevy rat has gone down in history without many of the nicknames it deserves.