[chevytruckluver]

that is some bad news about your block. I would locate another block, for the money you spend trying to bore the mains I bet you could find another block. Plus if you have to bore the cylinders to .60 over that means new pistons as well. .60 over does not scare me, I have owned several small blocks that were .60 over.
keep that crank what ever you do! IIRC you put that crank in a normal 350 block and you still have a 327
Have you considered a crate motor?
or do you have something special in mind for the 1st gen chevy engine?
Have you thought about going to a LS? you can buy a low mileage vortec and overdrive tranny from a late model chevy truck and get 20 mpg with some very good horsepower, for less than 2k complete
food for thought