Buick named the Straight-8 engine 'Fireball'. The company produced them from 1931 to 1953. It developed that Inline Eight engine (Straight Eight) 1931 as a more powerful alternative to their inline-6 engines.

A short video about the Buick inline 8 engines is here on Youtube.

This animated image reveals the inner works in this cool cut-away sketch. _{[Source: Wikipedia]}

Buick Inline Eight Engine History

Buick sold the engine in different displacements depending on the model of car and the year. The company constructed it upon two distinct block castings. Enthusiasts of the early 1940's and 1950's years know them for durability and longevity. Buick constructed these Inline Eight's very well. They were comparably heavy, which contributed to the robust build.

The smaller displacement versions internally resembled the inline Chevy Straight Six, with additional cylinders.
The large block version (used in large models like the Roadmaster) was considerably heavier. The weight adversely affected vehicle performance and handling. Which actually wasn't a big deal - buyers didn't expect a sport car anyway.

Buick Inline Eight Engine Production

Typically GM used cast-in-place bearings that make it somehow difficult to rebuild these engines. Buick's Straight-8 production ran out in 1953. More technical details about these engines we can see at the Buick Inheritage website. Buick finally replaced the Fireball engine with the new V8 322ci.

The engine displayed here is a 320 block that was pulled out of a 47 Buick Roadmaster. It is definitely original. Note: Another engine, inside a 1947 Buick.

A short introduction about this Inline Eight engine is also in the classiccarszone Channel on Youtube.

At the Auction
Note: Auction has ended!

My Buick parts book shows the block will fit any 1946 through 1948 Roadmaster with a manual transmission.

Spins over freely. It is offered here for parts or to rebuild because of the age. This only because no one can say for sure in what shape the interior is.
The paint on the valve cover is light blue and definitely original.