The block isnt a traditional bbc, its the Vortec 8100, which is a tall deck block with a 4.250 bore, and a 4.370 stroke which makes it a 496. From what ive read, the blocks walls are suppose to be very thick but not siamesed (whatever that means).
And one last thing. I know not too mant people are familiar with this engine and for those who are, the opinions are all over the place when it comes to the engines potential. I got this engine complete over a year ago for $600 with everything still attached to it and 6x,*** miles. My cousin and I are trying to put together a turbo build for it and then drop it in his 87' 442. The only reason i'm interested in increasing the bore size is because its a known fact that the stock rods and pistons dont like to be revved past 5grand, so why not squeeze more cubes out?