Someone is gonna sell me an engine for my LT230S, they said theirs will fit a 1985-1988 LT230S and I have a 1985.

They said it has a new Wiseco .20 over piston kit installed with 2 hours break in time one it.
It doesn't smoke and the only problem mentioned is this:
"cylinder was bored to 20 over with new wiseco piston kit installed, and the
valves were adjusted to accomodate the piston work. i also installed a new
stator cover. the chain did pop and crack the inside case, but was welded
and holds oil pretty good. it does leak a tiny bit because i didnt use a
gasket, just silicone. but nothing that couldnt be easily fixed. everything
thing else is in perfect shape."

My old motor is seized but has a good cover but what does he mean by "inside case"?


Also do ya'll think the piston work makes much of a difference?