If it's a factory 340 car then either you restore it or clean it up and flip it for a profit. If the 340 was added, find out what the engine came out of and sell it off separately. Or were you planning to swap out the 383 in your Demon?
It's a factory 318 car. The 340 is a '69 but I'm not sure what it came out of. I'll be swapping it into the Demon initially as I build up the 360 I have sitting around.