This tall deck aluminum block can be bored to 4.160", and stroke to 4.125" with minor modifications. The deck height is 9.525" with a 1.125" deck surface that can be machined as low as 9.000" . The bores start at 4.119" and can be bored to 4.160" with a 2.65" main bearing size and the camshaft is raised 0.391" from production locations. Pan rails are spread 0.400" per side for clearance of connecting rods.The main caps are four-bolt design of 8620 steel with the three inner middle caps having ball-end outer studs that are angled outward at 20 degrees to anchor the caps to the strongest part of the block. The four-bolt front and rear caps have straight outer bolts for oil pan clearance. The main cap hardware includes premium bolts, centerless gronud studs and 12 point nuts. The rear main uses a 400-type two-piece rear seal. This block uses a priority main oiling system and is a dry sump design with no provisions for an internal oil pump. The oil filter pad is eliminated so the starter can be mounted on either sideand the fuel pump boss is also removed.Use can bearing kit P/N 12370843.