Yes it is
not worth changing the crankshaft, better to swap the engine with new or used engine, now if it is the camshaft that is more cost effective.
The camshaft is most likely out of time relative to the crankshaft.
Belt, tensioner, idler pulley, H2O pump, camshaft oil seal, crankshaft oil seal, oil pump drive seal and gaskets.
No.
Go in the PCM with a scan tool and relearn the cam/crank values. I'm not 100% on this, but I think you have to have a Chrysler scan tool to do it.
Or the Crankshaft sprocket? it fires up but runs really badly, the timing marks all line up perfectly after changing the cam belt
changing the crankshaft sensor
There is no way for us to know that.
I'm not sure what a k series engine is but , if you disturbed the timing chain/belt in the process of changing the head, the camshaft may be out of time with the crankshaft. Be sure the timing marks are lined up and don't try to force anything to move otherwise you will end up with bent valves or worse, damaged pistons.
Yes. The camshaft determines valve lift, duration and timing. By changing those specifications the engine performance can be significantly modified.
Not changing the oil and filter can cause the crankshaft's journals to become egg-shaped.
2000 Sebring 2.5 was dying at odd times (like while driving on the freeway). Sometimes the tachometer would go to 0, then the engine would kick on again, sometimes it would die and then would be hard to start. Turned out to be the crankshaft sensor. Neighbor had the same car and tried to change the camshaft sensor (which is integrated with the distributor cap), and he ended up having to change the crankshaft sensor too. I recommend changing the crankshaft sensor first.