I have futher: head casting number 10141279, I think these are oval port closed chamber (100cc) vortec 7400 heads. Camshaft AC2416216 is laser etched near the first lobe near the front of the motor, pushrod guide plates are stamped RADAR, Crank casting number 10114188 (cast). It does have the roller lifter spider plate, hydraulic roller lifters, 4 bolt mains, the block has a tag marked "manuafactured for GM part number 12491330 date 1-2006, not much luck finding that # on the net. It has a six bolt cast aluminum timing cover. Any help would be great, thanks