When Mopar designed the B and RB motors there was no intent to make the main webbing thick enough to support 2 bolt crossing through that webbing to help strengthen the bottom end, DON'T do that Drilling through the main webbing is asking for a disaster to happen later when the main webbing fails and you run over the crankshaft
I have replace the stock main caps with both Ductile iron and aluminum along with ARP main studs because at that time that was the only option in trying to improve the strength of the stock RB and B blocks, not so any more
I'm buying new better blocks so I can really twist the tail of the Tiger to make the new motors wail like a banshee
Save your money on buying them and invest it into a good block