My64,
Welcome to CHR! From what I see, SBC 350's from '68 to '74 were simply the old 327CI blocks with a longer stroke, and the 327's didn't have a lot of "extra" meat in the cylinder castings for boring. In 1975 the 350 got a new block, and those built from '75 on were beefier than their predecessor's, so you might get by with a heavy bore, but why? Like Gasser says, it's a lot like the old 283's, you're pretty safe with a 0.060" bore on a post '75 block, and you might do just fine with a 0.080" bore but you might also "hit water", or thin a wall to the point that you need a sleeve to save the block. Worse, you might thin a wall just enough to be a problem, and not know it until you're chasing water in your oil, or worse. At least that's my understanding.

You'd be safer sticking with a 0.030" (355CI) or even 0.040" (357CI) bore, and chase your power needs in the heads and valve train. Share a bit more about what this is going to be dropped into, and people can jump aboard and give you a lot of good advice.