The main webbing is important but equally important are the thickness of the thrust side ribbing in terms of how well the block was cast. This one was a -2

This 230 I used for my 517 was about average in terms of the 230 main webbing but it was an exceptionally cleanly cast block with very strong ribbing and a very straight cam bore. of the I don't know how many B/RB's I've built over the years this one jsut fell together and turned super smooth. Expert Machining of the block and crank go a long way in terms of the motor not fighting itself....the webbing is a key factor but even the worst 400's I've seen are still thicker inthe main webs than nearly all 440's.

I've seen several thick web blocks that had bore thrust sides so thin they needed sleeves to even go +.030. And some may have horrific cam core shift. Webbing is important but to me it's not the single most important factor in block selection.