440 valve rocker arm shaft questions

The Mancini rockers are Harland Sharp bodies without the roller bearings, I've heard nothing but good things about them. They seem the best value for dollar, and you don't need a lot for a flat tappet, but the stock rockers aren't adequate. If you can find the Erson/Crane/Mopar ductile iron rockers, those are perfectly adequate as well. S/F....Ken M