The trouble with buying an engine that has had a prop-strike, is that unless you strip it and do a full shock-load inspection and NDT analysis of the crank, you won't know whether you've bought a great motor or a new anchor until far too late. No vendor of said motor is going to agree a sale to you subject to the strip, inspection and test as - until it's opened up - the motor is like schrodingers cat; simultaneously both alive and dead...
https://en.wikipedia.org/wiki/Schr%C3%B6dinger%27s_cat