Lesson plan
Polyspheric
The Polyspheric engines were V8 engines produced by Chrysler from 1955 to 1958 as lower-cost alternatives to its Hemi engines. These engines were based on the Hemi engines, using the same blocks and crankshaft parts, but completely different cylinder heads, pushrods, exhaust manifolds and pistons. They were called Polyspheric or Poly engines, because they featured polyspherical-shaped (meaning "more than one sphere") combustion chambers. These were formed by two shallow concave domes where the intake and exhaust valve seats were. Because these engines needed a less sophisticated rocker setup than a true hemi, with only a single rocker shaft in each head, they were also cheaper to produce and lighter. In the Chrysler literature, the Poly engines were also called single rocker shaft (SRS), while the Hemi engines were called dual rocker shaft (DRS). These engines replaced Chrysler's flathead inline-six in the division's lower-priced cars, and were themselves gradually replaced by the Chrysler A engine beginning in mid-1956.
Article summary
The Polyspheric engines were V8 engines produced by Chrysler from 1955 to 1958 as lower-cost alternatives to its Hemi engines. These engines were based on the Hemi engines, using the same blocks and crankshaft parts, but completely different cylinder heads, pushrods, exhaust manifolds and pistons. They were called Polyspheric or Poly engines, because they featured polyspherical-shaped (meaning "more than one sphere") combustion chambers. These were formed by two shallow concave domes where the intake and exhaust valve seats were. Because these engines needed a less sophisticated rocker setup than a true hemi, with only a single rocker shaft in each head, they were also cheaper to produce and lighter. In the Chrysler literature, the Poly engines were also called single rocker shaft (SRS), while the Hemi engines were called dual rocker shaft (DRS). These engines replaced Chrysler's flathead inline-six in the division's lower-priced cars, and were themselves gradually replaced by the Chrysler A engine beginning in mid-1956.
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Discussion questions
- Summarise the article in your own words. Which single claim would you verify first, and why?
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- If two sources disagreed about one of these facts, what would you need in order to trust one over the other?
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Key claims and bibliography are generated from the same tracked claims and sources as the article page.