I've had some pics around and it looks like I may have enough information to assist you in a rebuild. Perhaps in the future I can add/edit pics and info.   Lets assume that you already have the engine apart. One thing is get the block and parts hot tanked/ cleaned   https://www.enginemachineservice.com/jm3.jpg     Nest step would be to have it Magnafluxed for cracks. i would suggest that you find a shop that uses the wet method machine like this one.. The