Unlike most other car makers at the time, Buick had been using a valve-in-head/OHV overhead valve design or I-head since their inception and continued this practice in their straight-eight designs.
The engine was sold in different displacements depending on the model of car and the year and was constructed upon two distinct (possibly more) block castings.
The smaller displacement versions internally resembled the inline Chevrolet straight six, albeit with additional cylinders.
The large block version (320 cid and 345 cid; used in large-chassis models such as the Roadmaster) was considerably heavier and this weight adversely affected vehicle performance and handling.
In earlier years the engines used cast-in-place bearings that were then machined, which made engine rebuilding an expensive procedure, but after 1937 they began using drop-in bearings.
The last year for Buick's straight-eight was 1953, but only in the lower-cost Buick Special.
All other lines using the same basic chassis received the new V8 322 cu in (5.3 L) Nailhead.
Starting in 1954, the Special received the V8 as well.

1952 Production Engines and Ratings
Unlike most other car makers at the time, Buick had been using a valve-in-head/OHV overhead valve design or I-head since their inception and continued this practice in their straight-eight designs. The engine was sold in different displacements depending on the model of car and the year and was constructed upon two distinct (possibly more) block castings. The smaller displacement versions internally resembled the inline Chevrolet straight six, albeit with additional cylinders. The large block version (320 cid and 345 cid; used in large-chassis models such as the Roadmaster) was considerably heavier and this weight adversely affected vehicle performance and handling. In earlier years the engines used cast-in-place bearings that were then machined, which made engine rebuilding an expensive procedure, but after 1937 they began using drop-in bearings. The last year for Buick's straight-eight was 1953, but only in the lower-cost Buick Special. All other lines using the same basic chassis received the new V8 322 cu in (5.3 L) Nailhead. Starting in 1954, the Special received the V8 as well.
1952 Production Engines and Ratings
Buick Straight-8 engine