I don't recall the catalog listing for 216's in the 1960s Sears catalogs, but the Allstate and Craftsman lines from Sears in that time period were seldom "junk". Our local Sears stores did have a high reputation, in the 50's and 60's, for good automotive quality items. They had a very good warranty and return policy. (Their reputation did seem to slip in latter 70's -80's).
In the STL region Jasper was a known "re-manufacturer" (from Willow, Spg MO?) and I knew a guy who worked for them in the 60's.
The source of the re-manufactured motor may have been reliant on the closest re-manufacturer that could truck , or rail , to the district Sears.
In 1958 JC Whitney sold Chevrolet "Used Blocks and Heads" and a 1931-51 wo/PG was $46.20 and 51-55 w/PG was $69.60. The 1958 JC Whitney also sold what they called Gold Bond Quality Guaranteed Precision ReManufactured Engines ; Chevrolet was $133.50 w/exchange and 6 month guarantee.
A 1952 Newhouse Automotive Industries catalog has Full Race Engines to ship via truck or rail , "Blue Hornet" GMC or Chevrolet (Racing Built & Balanced) High Standard - $580 and Deluxe Finest $795 . That was a lot of money in 1952, and Newhouse said to state whether you wanted "road or track racing, or sports car use".
