This is a L78 CKO stamped long block. The numbers are as follows: Block casting: 3999290 Dated E2471. Pad stamp: TO928CKO. Heads: 3964291 Dated E171(both).
This block is .040 over(actually .020 over its original 402 size) with no machine work required. There is a very nice sleeve in #5 that is virtually undetectable. The crank is very nice and does not need any machine work. The rods are 3/8" dimple with very nice Keith Black pistons. The heads look very good and have no porting or other mods. The pushrods and balancer are also included. I would install new bearings in this engine and run it. This engine spent most, if not all, of its life in a fresh water jet boat. The 71 date indicates that this engine was destined to be used as a warranty replacement in a Camaro or Nova L78 375HP and a manual trans. Perfect replacement for your non original engine L78. I can post pictures if anyone is interested. $3000.
Jason