I think part of this is due to
California’s emission standards.
It’s almost impossible to build
a hot rod in California. Titling
a special built vehicle is a
nightmare, as anything built has
to have current smog requirements.
The Rat Rod craze has many hitting
the junk yards, and proof of
ownership for any vehicles and
parts is quite a process.
Hot rodding has its roots in Prohibition. Moonshiners would modify their flathead Fords or whatever they were running to handle the weight of all that booze and keep a step ahead of the police. Many PD’s in turn modified their cars and a “horsepower war” ensued. After Prohibition the first cars the FL State Troopers used were base model 1939 Ford coupes with the larger more powerful Mercury flatheads, like one of the first supercars, the same principle behind the first Buick Century’s, basically Specials with the bigger more powerful Roadmaster straight 8s, and of course the GTO decades later. This hot rod craze really took off after WW2 in southern CA.