it depends on how "rebuilt" it is,,there is "rebuilt" and "rebuilt" there is also "rebuilt" it can loosely mean taken apart and cleaned a lot and put back together with a new gasket here and there and an o ring or two,the next stage is the same thing but more gaskets and o rings,the next stage is a fully rebored and measured and machined and everything else the rebuilt term really should mean,,a thousand dollars?dont forget this should include a new clutch and any transmission trouble sorted,for example if the head looked ok in the guides and was cleaned up and put back on with new seals and valves re seated its used not rebuilt.