I don't know if Mancini still sells them or not but they offered a Harlan Sharp rocker with a bushing instead of rollers. If they had them when I was building my 493 I would have bought them. I have about $550 in my Iskys with shafts and new hardware from RAS
I would not run rollers on a street engine(although I know guys that do and have for years) Just my personal preference Less things in movement less things to go wrong.

Gus