From Wikipedia, the free encyclopedia
Rat rod is a newly developed name for the original hot rod style of the early 1950s. The term rat rod is considered derogatory to many traditional hot rod builders, but new fans of hot rods who notice the difference from yesterdays shinny hot rods to today's primered, lower and more radically designed hot rods call these cars rat rods. A rat rod is usually a vehicle that has had many of its non-critical parts removed. They are usually finished in primer-like paints and are often period correct. They are very often the conglomeration of parts and pieces of different makes and models.

A typical rat rod is an early 1930s through 1950s coupe or roadster with the body set low on the frame, fenders removed, whitewall tires, big-little tire combos, exposed engine bay, home-made upholstery, and lots of power. A Rat Rod is considered to differ from a Hot Rod in a number of key terms. A Rat Rod is generally considered to be a home built, low budget, one off custom that is still often driven and has many flaws and/or imperfections.

http://tribes.tribe.net/ratrod