You are building this to compete with a Chevy 454 right?
Glad to see you pulled the trigger on a second block if you found a period correct one for a restoration. I picked up a 383 in Oregon for $100.
At a minimum I would pull the heads and look at the bore. You may not want to "over bore" but the ridges may dictate otherwise.
I disassembled my 383 and had the shop Hot Tank, check the deck, align hone the mains, and will be boring once the pistons come in. As part of their block "prep" flat price they will be installing expansion plugs and new camshaft bearings.
The benefit if it all checks out is replacing new bearings and pistons rings anyways! Second, even if it is perfect I would recommend having a shop balance the rotating assembly.
