Description: Lighten up your big block Chevrolet engine. These GM Performance Parts ZL1 aluminum engine blocks feature an improved design of one of the rarest production engines ever built--the ZL1 aluminum big block used in 1969 Camaros and Corvettes. They feature a new casting made from 356-T6M aluminum alloy and have a 4.240 in. cast iron liner that can be bored to(more)

Description: Lighten up your big block Chevrolet engine. These GM Performance Parts ZL1 aluminum engine blocks feature an improved design of one of the rarest production engines ever built--the ZL1 aluminum big block used in 1969 Camaros and Corvettes. They feature a new casting made from 356-T6M aluminum alloy and have a 4.240 in. cast iron liner that can be bored to 4.300 in. The engine blocks allow for crankshafts with a maximum stroke of 4.375 in. and held in by 4-bolt splayed steel main caps.Other highlights include:* Thread-in freeze plugs with O-ring seal* 2-piece rear main seal* Provisions for wet or dry sump oiling systems* Provision for mechanical fuel pumps* Compatible with all types of cylinder heads (minimize)