I buy them out the junkyards here for 500 or so. Bought a 6.1 with spun rod bearing on ebay for 600, set up freight which was 85 bucks... just got to shop around.

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