.030 is not an issue. Remember the 383 Chevy is based on cutting a 400 crank .200 on the mains to fit the 350 block. And for circle track motors the common thing is to use the Honda 2.0 rod journal diameter down from the Chevy 2.100. Before affordable cranks we’re available this was done on stock cranks.I agree with this.
Remember this is a 330 crankshaft, so it is way stronger than the lightweight POS crank this block came with but is heavier. There is actually .040" bearings available for the SBO from King. I will ask Mark this question.