Guess what, they screw up too. This is a pair of their 5321 hydraulic retrofit roller lifters for an LA. I had been fighting an oiling issue with one lifter. I thought I just got a piece of trash in it. Called Hughes Engines and ordered a single pair because you can't take them apart as the pushrod seat won't clear the rivet for the link. So curiosity got the best of me and I drilled the rivets and took them apart. So looking at the pics the first one is the good lifter. You can see where the oil hole in the body intersects with a relief cut into the inside of the lifter body so the plunger doesn't block the oil flow. In the second pic you can see where the relief isn't cut deep enough to intersect the oil supply hole. Now will Dave warranty this for me? I'm going to call them and see what they say.