In '56-57;
The Trademaster 265 and/or 283 V8's were considered "Light duty".
The Taskmaster 265 and/or 283 V8's were considered "Heavy duty".
In '58-59;
All 283's were Taskmasters, and 265's were no longer available.
in line 6's were Thriftmasters.
big block 348's were Workmasters.
