I'm with Curtis on this you can do it but there are consequences, i run a 377" 2 bolt main and even with a gurddle there's evidence of main cap walk, and even with the block filled to the water pump there's still ring seal problems and i don't think i have much over 600 HP if that. We have a couple 434" that run good, but all the above still happens.
Bottom line if you can afford it go to an after market block, i bit the bullit and bought a Dart little "M" for my 434" that i'm building.
PS, Hink, i hope you guys bought the 350 main blks., since most everyone i know is going that way.Also i saw an ad for the new SHP blocks here on RJ, for about the same prices you mentioned, but i don't think they mentioned fixing the lifter bores.
JMO
Zip.