Original GM #3916321 Corvette 427 Engine Block. This is the high performance 4-Bolt Main Block used in RPO L71 435HP TriPower applications in Corvettes. Also used in 425HP L72 COPO Chevelles, Camaros & Passenger Cars. Fresh machine work including rough bore to .037---will finish hone to .040, Line Bored, Magnufluxed & deck just enough for a clean pad. Dated F167 (June 16, 1967)--for early to mi...