Fords are characterized by slightly higher displacement V8 engines (Ford 302 vs. Chevy 300, Ford 351 vs. Chevy 350, Ford 402 vs. Chevy 400). Ford is also a more economy minded producer in more modern times, while Chevy is less so because of the use of the Buick and Olds brands. In performance, Chevy engines are often slightly more powerful, the 350 normally produced a maximum of 310 hp opposed to the Ford “windsor” 351 that made 290. Ford is known for many smaller sized cars, like the Escort, Tempo, and Marshall, while many GM cars are Buick, Pontiac or the retired Oldsmobile–although there are some Chevy versions of the smaller cars. The Chevy Small Block V8 is a very versatile engine, having been used in every GM brand, by marine stern-drive companies and even in ultralight flying machines.
It is a common hotrodding engine. The Ford Windsor is prized because it was the first pony-car engine. Ford is known to be the original pony-car manufacturer, starting witht he mustang, whose name (a breed of horse) created the term. Although with the flat-head V8 ford began the hotrodding trend in the ’32 duece roadster, starting in the 70s Chevrolet took control of hotrodding, mainly because ford went through many different engines (MEL, Lincoln Y-block, Ford Y-block, Ford FE, Ford Windsor, Ford Cleveland, Modular V8 or V10) while Chevrolet still makes similar engines to those found in ’60s corvettes and camaros, the Chevy Bigblock and Smallblock.
As far as economy goes, there is very little difference between the two companies.
It is interesting to note that both companies supplied parts for AMC cars–the gremlin could have a Chevrolet transmission hooked to a Ford 170 I6–proving there is in reality very little difference between their products.
Between the Ford Galaxie and Mustang, and the Chevy Nova both companies garner much respect from hotrodding enthusiasts.