I picked up a 6.1 long block with a spun bearing last month... under 750 total including freight. I've seen some other good deals on them on ebay also. Just need to look at the right time.

68 Road Runner, 69 Belvedere, 71 Challenger Vert
340 barracuda, 01 Ram CTD, 95 Ram, 04 Ram, 85 Daytona turbo Z
66 GTO, 06 Magnum RT AWD. 07 Ram CTD, 07 Ram