looking for my original 340 block

I am restoring a 1970 dodge dart swinger 340 4speed car. The tranny is numbers matching but the engine is not. Figured its a long shot but figured I would see if anyone around has it. The story I was told was that the car is from Illinois but the car ended up in Michigan. The number I am looking for is HOR129645. Would love to have the original engine block to make this car numbers matching. Is there any other places I can post or look for this block?