I have this set and the related set from 1971 that was updated through 1978. The 70 set with blue ink backs was 66 cards. The 71 set has backs with black ink and initially had 68 cards, but was updated through 1977, maybe through pack inserts in subsequent issues, or maybe with leftover inventory of other WS cards. The 71 set ended up with 75 cards and the subsequent 71 through 75 series cards can be pricey
Most people are familiar with the Fleer baseball sets from 1959 through 1963, but Fleer put out many baseball issues from 1964 through 1980. Since they involve mostly stickers, emblems and pennants, and cards involving prior era players ( there is though a Don Drysdale puzzle card set), they have had less hobby appeal and notice
If you type in a internet search for "the fleer sticker blog project" you will find a great site which covers all the many Fleer baseball and football issues from the 60s, 70s and early 80s. While a few of the sets appear in the SCD Standard Catalog, most do not. The World Series sets are included in the site and there are illustrations and scans of all the sets listed and discussed, including a discussion of the packaging and distribution of these issues in packs. Link below
http://r.search.yahoo.com/_ylt=A0LEV...NLGyIkXexfTpk-