Any Vt275 engine replacement options?

I have a chance to buy 2 2008 Cf 500 in pretty good shape the inside cabin on one is a little rough but nothing major. I can get both trucks for a total of $6,000 but both of them have major cracked engine blocks so I'm going to have to replace them, should I even attempt to have a mechanic swap them out, the cheapest used vt275 I've found is $4,500, and I'm assuming there's no less expensive engine I can put in, so in the end those trucks will end up costing me $10,000 grand a piece, is it worth it? I plan to use them only locally, driving about 200 to 300 miles a day as I am going to try to get a contract as a same day delivery drivers for online furniture stores somewhat like ikea.