375 HP 408cui qustion

A friend of mine bought this used Blueprint engine mentioned above. The seller said they had a main bearing issue and fixed it. I guess they made it wrong :-( The engine is realy hard to turnover, almost impossible with a regular ratchet, even if i reomove the sparkplugs. So my question is with a torque wrench, what should it take to spin ? The starter (90s dakota starter) also has problems to spin the engine with the Spark plugs in it:-( It broke two starters already :-(