A ritter block is expensive and still needs tons o expensive machine work to be used. There are plenty of compareable chubby blocks that can be bought, fixed and run for less than buying a ritter block.

A magnum does not use a ball and stud and pretty much anything built with
a magnum head or LA (factory heads anyhow)don't make enough RPM to take advantage of a shaft rocker system.

A magnum ain't so great just fer the roller cam... the heads are better flowing on the intake and exhaust than any factory LA, nice machined valve cover rails with 10 bolts that don't leak, re-useable valve cover gaskets, ex bolts that don't have watter in em, no heat cross-over, one piece pan gasket, much stronger block, cheap reliable roller cam, much more compression tolerance than any LA heads, should I keep going I am out of breath