Mine was $1,000 for all the block work and parts (new pistons, rings, etc) to go from a 302 to 306. $600 to disassemble, take out and reassemble. The guy who reassembled mine really jacked it up, so make sure you take it somewhere reputable.
I disassembled my shortblock, brought it in had the block hot-tanked and honed, decked, and all new main, rod, and cam bearings installed, all new freeze and oil galley plugs, new rings on the factory pistons (even after 150K miles they found no significant bore wear), and ARP main and rod bolts put in. This was done with them reassembling the rotating assembly for $860 (this includes all bearings and parts, etc.). This was done at a very good and reputable local shop that was very good about understanding my wanting to reuse the factory pistons to save some cash if possible.........they never tried selling me anything other than their machining and assembly service that I asked for.