at887 are the milk bottle lifters generally used on the early steel cam motors. Around 1990, sealed power changed the material so that you could run a new cast iron cam in an early motor that original had a steel cam. That being said, can you confirm what year your block is because if its a 59 or up 261, one that eliminated the steel feed line from the rear cam bearing to the head (behind the lifter side cover on the 55-58 motors), those motors used a direct galley feed from the lifter galley and you would want to use the at874 solid lifters (that look like the 55-62 235 lifters.
https://images.search.yahoo.com/search/images?p=235+chevy+lifters&fr=yfp-t&imgurl=http%3A%2F%2Fwww.chevsofthe40s.com%2Fimages_product%2Flarge%2F5230850.jpg#id=0&iurl=http%3A%2F%2Fwww.chevsofthe40s.com%2Fimages_product%2Flarge%2F5230850.jpg&action=click
the depressed area in he middle allows to oil to flow past.
