It does depend on the degree of "refurbishment". If you want to evaluate and re-use all re-usable components without replaceing most common items you might get away with the costs you mentioned.
A re-built short block will cost about the same since only worn components are usually replaced.
In this area I would guess-timate an engine rebuild will cost from 1500 - 2500 dollars. If you dis-assemble and re-assemble the same components and only have the valves ground and have it bored for oversize pistons and install crank, pistons, bearings, cam and internals yourself you could probably get away with about half of that amount.
There are so many parts to replace in a total re-build it would be difficult to accomplish for under @ $2000 in this area.
Powerband