The GA16 has a closed-deck cast iron block. You can sleeve it for sure, but if you bore too far (and they are thin-wall castings), then you will hit the water jackets. It was never designed to use wet-sleeves, therefore to expose a new iron sleeve to coolant you'd end up opening a whole new can of worms in terms of sealing problems.
Better to limit the bore to something reasonable. I'd recommend .5 mm/.020" over for boost and a max of 1 mm/.040" for an N/A application. You could physically go further, but flexing cylinders do not allow for good ring seal so you'd really be going backwards.
For greater strength (as in running ridiculous boost) you could sleeve the block with a smaller ID ductile iron sleeve, and re-bore it to stock dimensions (76 mm). You'd give up a few cc's, but if you want 30+ PSI of boost it's the way to go.