The older units - 68-69. Pressurized the shaft.Used the larger 3/8 ball end on pushrod cups. Worn bushings allowing oil to escape Finally the roller tips with flat spots preventing smooth action against valve tip. Then they may require tall V/C. I bought a used set.Had to buy new shafts Had to replace a Bunch of adjustment screws, Called KB. + had to order replacement bushings then we had to put them on Bridgeport to cut the bushings to a size listed in Steven dove book which differed from GM manual. Think I spent 200 more than new would have cost. - But they worked.
Someone bought them. They had no shaft hold downs or bolts, shaft end retainers, no shims between spacers, or needle bearings. Some extra fabrication and they would be better. Good shafts & bones though.... https://www.ebay.com/itm/264859102453
When the Original poster.brought t to everyone's attention. It was snatched up by someone else. One thing I learned was to keep quiet.