[Shuie]

Not enough info....

How good is your mechanic? What kind of upgrades does either motor have? What kind of warranty will your mechanic offer with his documented motor?

Get compression and leakdown numbers on the $4k motor and check for broken studs. If its clean, Id go with it over a similar $6k+ documented motor that had not been significantly upgraded when it was rebuilt. These engines are pretty solid. If they are healthy, maintain them and keep oil in them and they will live for a long time.

good luck