The first Buick made for sale, the 1904 Model B, was built in Flint, Michigan. There were 37 Buicks made that year, none of which survived. There are, however, two replicas in existence: the 1904 endurance car, at the Buick Gallery & Research Center in Flint, and a Model B assembled by an enthusiast in California for the division's 100th anniversary. Both of these vehicles use various parts from Buicks of that early era, as well as fabricated parts. These vehicles were each constructed with the two known surviving 1904 engines.
The power-train and chassis architecture introduced on the Model B was continued through the 1909 Model F. The early success of Buick is attributed in part to the valve-in-head engine patented by Eugene Richard. The creation of General Motors is attributed in part to the success of Buick, so it can be said Marr and Richard's designs directly led to GM.
The basic design of the 1904 Buick was optimally engineered even by today's standards. The flat-twin engine is inherently balanced, with torque presented to the chassis in a longitudinal manner, actually cancelling front end lift, rather than producing undesirable lateral motion. The engine was mounted amidships, now considered the optimal location.
Source: Wikipedia, 2011