World Products American-made Merlin III cast-iron big block is now available with an extra .050″ of deck height. For the Chevrolet, this new feature allows greater versatility in selecting connecting rods and particularly in selecting pistons with additional compression height to keep the ring grooves and wrist pin bore isolated.

The new Merlin III variant is available with a 9.850″ or 10.250″ deck height. Cylinder bores are semi-finished at 4.595″ allowing for a finish hone to suit the specific pistons and ring packages chosen by the engine builder. Cylinders can be safely bored to 4.625″ and with minor clearance the 9.850″ deck Merlin can accept up to a 4.375″ stroke crankshaft and the 10.250″ deck can accept up to a 4.750″ stroke. Nodular iron 4-bolt main caps are used with ARP fasteners for maximum strength.

The Merlin III is cast from high strength iron alloy and precision machined on CNC machining centers for dimensional accuracy. World’s priority-main oiling system delivers lubrication to the critical main bearings first for reliability at high rpm.

Head bolt holes are blind-tapped and do not go through into the water jackets. The valley has bosses machined for four extra head bolts to accommodate race heads which utilize this feature. The oil pan rails are machined to accept both stock pans and aftermarket race pans. World’s Merlin III big block is an ideal choice for a wide range of performance engine configurations.

Part numbers for the upgraded blocks are:

081107 MERLIN III bare block,   9.850″ x 4.495″ Nodular splayed 4-bolt caps

081117 MERLIN III bare block, 10.250″ x 4.595″ Nodular splayed 4-bolt caps


Like all World’s blocks and heads, The Merlin III is 100% American made. World blocks are cast from high-strength iron alloys and are precision machined on CNC machining centers for unmatched accuracy. World’s new digital inspection equipment and quality verification procedures ensure dimensional accuracy and mean you can be assured of total quality and superior performance.

For more information contact World Products.