World Products has redesigned the famed Merlin Big Block Chevy casting, incorporating numerous improvements and new features. Designated the Merlin IV, this new block is sure be a favorite among racers and professional engine builders. New features include thicker main webs for increased strength and thicker cylinder walls which are nominally .310” @ 4.600” bore. The oiling system is revised with enlarged passages and cross overs in front, uses simple pipe plug type restrictors, .500 oil gallery is relocated so 55mm cam does not require lifter bushings. The block will accept cam journals up to 2.480” or 60mm Babbitt and 1.060” lifter bores. Also new are deck heights from 9.500” to 9.850” and 10.200” to 10.250”
High density cast iron construction = Priority main oiling = Front oil inlet and restrictor provision = Bores to 4.625 (4.245, 4.495 or 4.595 std.) = Cylinder walls .310” @ 4.600 = Valley accomodates OE roller lifters or use +.300” tall aftermarket lifters = 9.500” to 10.250” deck heights = Clearance for 4.750” stroke (10.200” deck) or for 4.375” stroke (9.800” deck) = Splayed 4-bolt main caps w/dowels & stepped register, ARP fasteners = 2.120” BBC cam bearing bore = Available 55mm babbit cam & .904 lifters = OE style fuel pump & starter mounts = Approximately 270 lbs.