Sonoramic Intake

B and RB are different widths?

Yep, thats true, but each side "tube" just bolts to the head, and it doesn't matter if it's a low block engine, or a raised block engine.
Those "Long Ram" manifolds, and "Short Ram" manifolds, (Sonoramic) were installed on both low block, and raised block engines, back in the day, until 1964.