Hydraulic lifters

If you want reliable flat tappet lifters, get your factory lifters re-faced [ or lifters that are 25 yrs old, before the CRAP lifters arrived on the scene ].
In Australia, we have been doing this for decades because of the high cost of new lifters. As long as the lifters are not too badly cupped, they can be re-faced. I have had lifters re-faced 2-3 times when I was experimenting with cams & needed a 'new' face for a new cam. They are the same hardness right through.