If you're going down this path, get the bare block hot tanked. I did a 'dirty' block clean with oven cleaner and a small scrubbing brush and gave the bores a quick deglaze with a scourer ball on a cordless drill as there were no signs of cosmetic wear on the bores on this particular engine (I finished it off with spray can degreasers as hosing down the inside of an engine block with water is asking for trouble) . If it's got a lip on it, it'll need boring. Likewise if it has obvious cosmetic damage like scoring or gouges. But if the bores appear to be undamaged but worn smooth, my deglaze trick will work (I installed new stock size rings and polished up the pistons) This may be advantageous as a little extra clearance on the bores with a turbo install is helpful - boost will force the compression rings to seal tighter. An engine with already tight clearances will more than likely snap piston rings.