It really depends on the engine you use and where you get it from. You can dig an LS1 out of a junkyard and hope it was well treated before and only pay $3000 or so. You can also go the crate engine route, which is much more expensive but reliability is awesome. Personally I have found a LS2 crate engine that makes 510hp and 480ft. lbs at the crank. It also costs $10,000 and it's brand spankin new.
I've got alot of saving to do if I want to go that route.
