Elliot Handler, co-founder of Mattel, decided to produce a line of die-cast toy cars to capture a portion of the small model car market that Lesney had with their Matchbox cars. The Mattel executives thought this was a bad idea. We all know how it turned out!
The original cars and trucks were introduced in 1968 in approximately 1:64 scale and designed to be used on associated Hot Wheels track sets.
There were sixteen castings released in 1968, eleven of them designed by Harry B. Bradley, with the first one produced being a dark blue Custom Camaro. Although Bradley was from the car industry, he had not designed the full-functioning versions of the real cars, except the Dodge Deora concept car, which had been built by the Alexander brothers. Another of his notable designs was the Custom Fleetside, which was based on his own heavily-customized '64 El Camino.
Those releases were
in no specific order)
Custom Camaro
Custom Fleetside
Custom Barracuda
Custom Corvette
Custom Cougar
Custom Eldorado
Custom Firebird
Custom T-Bird
Custom Mustang
Custom Volkswagen (designed by Ira Gilford)
Beatnik Bandit (designed by Ed Roth)
Ford J-Car
Hot Heap
Deora
Python (designed by Dean Jeffries, based on Cushenberry's "Cheetah" show car)
Silhouette