It's obvious that, that is a 3.4 stroker and if that is #1 or #2 main, that crack STARTED at the bottom of the main bolt holes. The preload, adds vertical pressure, evenly, only to the cap, itself and does not effect the main studs.
I posted this mod on ST and with that, I talked on the phone, for about 2 hrs, with a actual, mechanical engineer. He agreed that it was a structural, strength improvement. We agreed that it would be even stronger, if the pan rails could have been incorporated but, the girdle isn't wide enough for that. He has done a lot of research on these 289/302/5.0 blocks. Can you tell us where your mechanical engineering degree was issued?
I got this ideal after buying the girdle and putting it in place, then seeing that I could add this arrangement so, I did, just that.
It could be improved by furnace brazing the standoffs to the webs but, in my case, it's way to late for that. It took me over 6 mo, to get it out of the machine shop, as it is.