Hyd. Cam in a '98 360 block W roller lifters?

If it's a roller, I would stay with a roller. But you'll need new pushrods or adjustable rockers unless you get Comp or another cam company to grind you something that's NOT a reduced base circle....because as far as I know that's all that's available off the shelf is reduced base circle. I could be wrong...because I haven't built one off a factory roller block yet.....so I might not be a good source of info. I just saw your post and thought I would try to help. Maybe somebody with some more knowledge about the late stuff will chime in.