Hi I will help with your problem Please do not rate until all your questions are answered that way you wont have to pay twice Use reply to expert link.
Good morning I'm also certified in block cutting or a machinist,Were are the cracks exactly they allow some cracks at top off block but they cannot go up and down or all the way to a water jacket.
If the cracks go to bolt holes then there are inserts that can be installed also were liners sit on block deck we could cut out and install inserts and then the block would be ok.I'm afraid if you get your hands on another block used it would have same issue.The only way to get one is new or rebuilt.I would talk to a local machine shop they can get the inserts and cut the block to install inserts and then use new liners.While the block is still in the chassis so if you have not removed yet I would hold off until you know.
Don't forget to let me know were the cracks are or pictures and I could give you further info.

I think I uderstand but just to make sure is there any way to take pictures or fax pictures if you contact customer support they can help you I need to see the cracks to give my honest opinion.
On the cracks if the cracks are just under the liner flange and don't go beyond the flange area [meaning don't go down or sideways to bolt holes and or coolant passages then it would be ok but without seeing them I can't tell you for sure.
I don't know were you are located what needs to be done is magnafluxed the area of cracks and it will show how far the cracks go some times the crack will keep going and you won't be able to see with your naked eye so it is important to know before going further.
If you give me your location I can help you find some one to check the cracks.