Some quick poking around the internet shows that this is a fairly old and obsolete tractor. Connected to Mahindra somehow in the past but others report they can not get parts or service from anyone. Used is probably your only option in the US but there are over seas sites that sell parts for Chinese tractors. That may be your only hope
You didn't say why you want a block but one would have to guess yours is un-repairable for some reason. If you need a block, what other parts do you need? Gasket set? Pistons or crankshaft?
Have you looked for a different engine that might fit or be modified to fit? Anything can be fixed for a price, only you can decide if it is worth it or not. Having a new block cast by a foundry is certainly doable but probably exceeds the value of the tractor several times. As hard as it is, sometimes you have to "scrap it" and move on.
Good luck on your project.