Hal, with the GM Goodwench motors, the core is a more reasonable $100. The GM Performance motors dont have a core charge at all.

I used to go to a core vendor in Dallas that would let you browse thru their piles of stuff. We bought engines that had very few miles on them.....probably came out of wrecked vehicles. One friend got a 292 chevy six engine that was super clean with all the decals still on it for $100. When he pulled the head, the thing was new inside.