Like its sister General Motors divisions, Buick

Buick

Buick is a premium brand of General Motors . Buick models are sold in the United States, Canada, Mexico, China, Taiwan, and Israel, with China being its largest market. Buick holds the distinction as the oldest active American make...

 produced its own family of V8 engines to replace its straight-8 engines

Buick Straight-8 engine

The Buick Straight-8 engine was produced from 1931 to 1953 and sold in Buick automobiles. Like many American automobile makers, Buick adopted the straight-8 engine in 1931 as a more powerful alternative to the previous inline-6 engines...

. These engines came in many of the same displacements as those from other divisions, but were entirely different.
Buick first generation of V8 lasted from 1953 through 1956. It was an OHV

Overhead valve

An overhead valve engine, also informally called pushrod engine or I-head engine, is a type of piston engine that places the camshaft within the cylinder block , and uses pushrods or rods to actuate rocker arms above the cylinder...

/pushrod engine like the then new Oldsmobile "Rocket V8" engine. This engine became known as the "Nailhead" for the unusual vertical position of its small-sized valves, which were derisively compared to nails since their head diameter is rather smaller than other comparable displacement engines of the same era.