World Products all-new Merlin IV Block for Chevrolets

World Products all-new Merlin IV Block for Chevrolets

World Products has completely redesigned and re-tooled their famed Merlin big-block to achieve new heights in performance and ease of use for engine builders and racers. Starting with all-new foundry tooling and machining fixtures, World has made improvements to virtually every area of the new Merlin IV with the goal of producing the most technologically advanced and best performing cast-iron BBC block available today.

New features include thicker main webs for increased strength and thicker cylinder walls, which are nominally 0.310in @ 4.600in bore. In addition to the standard BBC 9.800in and 10.200in deck heights, further new deck heights have been introduced. These measure 9.500in, 9.850in and 10.250in. Their objectives? To allow greater versatility for specific engine combinations. Furthermore, head bolt holes are blind on all available deck heights and deck thickness is nominally 0.600in.

The Merlin IV is available with a 2.120in journal for standard BBC cam and standard 0.842in lifter bores, or with a 2.283in journal for a 55mm Babbitt cam and 0.904in lifter bores. Cam journals up to 2.480in or 60mm Babbitt and 1.060in lifter bores can be accommodated, but are not stocked by World Products. World also has increased the volume of the priority-main oiling system and added a front oil feed for dry-sump oiling systems. Other key upgrades include lifter oil feeds and restrictor provisions, which have been relocated to the front of the block.

The new block features siamese cylinder bores in 4.245in, 4.495in or 4.595in., which are finished at 4.250in, 4.500in and 4.600in respectively. Water jackets have been further enlarged for greater cooling capacity. Nodular iron or 1045 billet steel four-bolt main caps are standard and feature dual register to prevent cap walk. High strength 1/2in ARP fasteners are employed to secure the main caps. Bolts are used with nodular caps, studs with billet caps.

Cast and machined in ISO 9000 certified facilities, the Merlin IV is 100 percent American-made and subject to stringent quality assurance procedures to ensure superior quality and performance. This new block is sure be a favorite among racers and professional engine builders.

For more information contact World Products.

877-630-6651 ~


Part #DeckBoreCamMain CapLifter BoreRear Seal
911009.84.245STDNodular0.8422 PC
911019.84.495STDNodular0.8422 PC
911029.84.595STDNodular0.8422 PC
911079.854.595STDNodular0.8422 PC
9111010.24.245STDNodular0.8422 PC
9111110.24.495STDNodular0.8422 PC
9111210.24.595STDNodular0.8422 PC
950009.84.245STDBillet0.8422 PC
950109.84.495STDBillet0.8422 PC
950129.84.595STDBillet0.8422 PC
095013-559.54.59555mm BabbitBillet0.9042 PC
950179.854.595STDBillet0.8422 PC
9510010.24.245STDBillet0.8422 PC
9111010.24.495STDBillet0.8422 PC
091110-5510.24.49555mm BabbitBillet0.9042 PC
9111210.24.595STDBillet0.8422 PC
091112-5510.24.59555mm BabbitBillet0.9042 PC
9511710.254.595STDBillet0.8422 PC
910909.84.12STDNodular0.8422 PC

1 Comment

  1. I’m interested in the new Motown lightweight SBC block and prices for a 427 short block.


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