Help Needed

[Shazy4eva]

Hi was wondering if anyone can help me out on this really need to get motor back on the road 5 day's ago was on the motorway driving 70mph when all of a sudden loud knocking noise from engine as i slowed down to pull up on hard shoulder the engine cut off called recovery and the chap said that crankshaft is the problem towed it to the garage and got the engine stripped mechanic says that one of the bearings on rod con snapped of and grinded one of the crankshaft and the only option is to replace engine but i was wondering if there are specialists who can recondition the crankshaft also if i do replace the engine can i swap a avensis cd1 ftv engine into a previa the mechanic says that it's possible but the vehicle would have a heavy vibration