If you say a 351C is capable of turning 8000 rpm (and it is plus more) then take the ratio of the journals at that rpm.
2.75" / 3.0" * 8000 rpm = 7333 rpm
So a 351W at 7333 rpm has the same main bearing surface speed as a 351C at 8000 rpm.
I think the nascar boys are spinning 351C to 9000 rpm on a regular basis. I do not know what oiling tricks they are using. The factory Cleveland blocks had a poor
oil priority design, as most factory blocks do. A good block is likely more important.
PS
On my budget, I cannot afford the valve train to spin a 351W that fast anyway. For 400 HP you just don't need much over 6K rpm anyway.