World’s MERLIN series has earned a reputation as the performance industry standard for Big Block Chevy power. The cast iron MERLINS are available in both oval and rectangular port designs, with intake ports offered in 269cc, 320 and 350cc configurations. Choose the port size that will provide the optimum balance of flow and velocity for your engine combination. They are available bare or in complete assemblies that feature multi-angle valve jobs, Manley stainless steel valves and valve springs matched to camshaft requirements. These heads are also available in Marine trim, equipped with ultra high temperature Inconel exhaust valves and other special components.

Casting ID Number: WOR-042A
Material: High density cast iron
Cam Bearings: Standard SB Chevy
Cam Location: Standard SB Chevy
Maximum Bore: 4.200”
Cylinder Wall Thickness: .250” at
4.200” bore
Water Jackets: Expanded for better cooling
Lubrication: Priority main oiling system
Oil System Features: Integral boss for
front feed, boss for rear scavenge, rear main cap can accept wet sump pump
Filter: Integral mount for spin-on filter
Oil Pan Rails: Solid (stock width) clearanced for 4.000" stroke
Main Cap Material: Street and Sportsman blocks caps are made from nodular iron, Race blocks are made from 1045 billet steel (unlike competitors’ softer 1020)
Main Caps: Street block caps 1 thru 5 have 4 bolts, Sportsman and Race blocks have splayed 4-bolt caps (2, 3,4) and straight 4-bolt caps (1, 5)
Main Cap Hardware: 1/2" ARP and ring dowels used to locate main caps firmly into position (not antiquated standard OEM outside registers)
Rear Main Seal: Two piece SB Chevy
Fuel Pump: Stock location SB Chevy
Motor Mounts: Dual (frnt & side) SBC/ LS
Cylinder Head Bolt Holes: Blind tapped to prevent water leaks
Lifters Bosses: Clearanced for vertical bar lifters (can use std. height LS lifters)
Clutch Linkage: Standard mounts
Starter Mount: Stock location
Weight: Approximately 190lbs.