273 adjustable rocker arms

How is that ductile iron to work with?

It's not bad.. lock down the table, good sharp tool, lube....
on the other hand, if the rockers gall-up on the shafts, due to poor oiling, that is a completely different story.
It 'work hardens' the inside of the rocker where it galls up and it will destroy your hone. You have to get in there with a carbide bit and carefully knock out the galled up mess, then hone them.