Dongray, You may not need sleeving. Depends where the pits are. They may be in an area that's not crucial. The bore center can also be shifted to minimize the next oversize. All these Chev & GMCs get heavy #1 cyl wear at water pump area. Shifting bore ctr toward pump often allows .030 bore instead of .040-.060 bore. $ 1000 for the mentioned work is a good price. Would cost more in my area. I agree that you should seek another block,as suggested.
On lineboring: Usually only a thou or is all that comes out of block. The cam is off at about 45 deg. Not like many engs like a flathead Ford where the cam in directly above the crank. Chevs don't have problem with mesh or timing change in my experience.
David
