1973 340 price check?

Pay $300 for a .030 over block with 3 stuck pistons last year.
I have a .060 block I wouldn't sell for a $1000.
My .040 block has over $2000 in machine work.
So your block could be worth $100 to $3000 just depends on what it is and what kind of shape it's in and what other parts are included.