Lets not confuse the 59 degree to the lifter to pushrod angle, that is just scary! The lifter to pushrod angle is only about 12 degrees off the lifter angle. And I've never seen a lifter with that type of retainer. all the ones I've seen are circlip or at least formed wires. This drawing shows more than enough clearance to keep the ball end (even semi hemispherical) secure without interference.
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