All New Merlin IV Big Block Chevy


World Products has completely redesigned the famed Merlin Big Block Chevy casting, incorporating numerous improvements and new features to virtually every area of the block. Designated the Merlin IV, this new block is offered in all popular sizes and deck heights and is sure be a favorite among racers and professional engine builders.
New Merlin IV features include upgraded 35,000 psi iron alloy with added material in the main webs, cam tunnel and cylinder walls for increased strength. Cylinder walls are nominally .300" thick on the thrust side @ 4.600" bore. Material was then removed in non-affecting areas in order to maintain the original weight.

The block also has an increased volume priority main oiling system with a .500" main oil galley. A front oil feed for dry sump systems is incorporated with front oil cross-overs and restrictor provisions which now utilize standard pipe plug type restrictors.  The main oil galley has been relocated so that blocks with a 60mm cam will not require bushed lifter bores.
The Merlin IV is available with a standard BBC cam journal and .842" lifter bores, or with a 55mm Babbitt cam journal and .904" lifters. Cam journals up to 2.480" or 60mm Babbitt and 1.062" lifter bores can be accommodated.

 New deck height options are also available. In addition to the standard 9.800" and 10.200" decks, options for 9.850" and 10.250" allow more flexibility in designing component stack ups to optimize piston pin and ring pack placement. A new 9.500" deck height option is ideal for sub 500CI displacement restricted classes like NE Modifieds and Truck Pulling, allowing for lighter rotating mass configurations which improve acceleration.All deck heights are nominally .600" thick, feature blind head bolt holes and use standard length bolts or studs. The inside head stud provisions have also been revised to add strength by  extending the bosses below the deck thickness in the casting.The new block features siamese cylinder bores in 4.245", 4.495" or 4.595" which finish at 4.250", 4.500" and 4.600" respectively. Nodular iron or billet steel 4-bolt main caps are standard and are stepped and dowelled register and utilize ARP fasteners.

World Products blocks and heads are 100% American made and are subject to stringent quality assurance procedures to ensure superior quality and performance.



WORLD Products
7301 Global Dr.
Louisville, KY 40258