79 JD 850 worth fixing?

[metalbender]

Lots of those guys that sand the crank and call it good, sell it quick with a rebuilt engine.

 

[TimberHole]

Another issue I just noticed is that your rod appears to be shot. I had the same deal when I did my 950 and ended up on an Easter egg hunt for a matching rod. My goal was to match rod casting numbers but I think I eventually settled for a different casting number but nearly identical weight. I think I ended up with an extra rod or two if you end up repairing.