383 Block - Questions

You want to be careful - if it was me I'd buy a core block at standard bore because unless you test the bores you just don't "know".
I have a '69 383 here it was supposed to be used for a 496". But - it's already "only .030 over" and the cylinder walls are too thin for the stress. Keeping it at 4.280 still only gives .134" on the major thrust because all the bores on the driver's bank are offset to the minimum thrust side from core shift. If it was to go another .030 would put it at .119" on the major thrust. Needless to say the shortblock will be going up for sale and we're using another block but to the naked eye this block is "perfect and only .030 over".