From: Henry C. Dozier
Email: dozierhc@aol.com / 248 209-5630
Date: October 01, 2001
The 331 had the extension for the fluid-drive converter from 1951 through 1953. Chrysler removed it for the 1954 model year (1st for Powerflite trans). Then in 1955 they revised the water jacketing in order to be able to have a common block core layup for the Windsor 301 poly as well as the 331 hemi in NY and Imperial. The Industrial 331 in 56 and up were actually 354 castings that were underbored, so they have extremely thick walls.
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