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 to be a favorite among racers and professional engine builders.
New features include thicker min webs for increased strength cylinder walls which are nominally .310" @ 4.600". The oil 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 Babbit and 1.060" lifter bores. Also new are deck heights from 9.500" to 9.850" and 10.200" to 10.250".
- Material: High Density Cast Iron
- Deck Height: 9.500"10.250"
- Deck Thickness: .600" minimum
- Cam Bearings: 2.120" journal bore, also available with 55mm Babbit and .904" lifter bores
- Main Bearings: Standard Chevrolet
- Camshaft Location: Stock
- Lifter Bores: Indexed (stock .8437" bore)
- Bore: 4.245", 4.495" and 4.595"
- Maximum Bore: 4.625"
- Cylinder Wall Thickness: .310" at 4.600" bore
- Water Jackets: Expanded for better cooling
- Lubrication: Priority main oiling system
- Filtration: Integral mount for spin-on filter
- Oil Pan Rails: Solid (stock width)
- Crank Clearance: 9.800" 4.375" stroke, 10.200" 4.750" stroke.
- Main Caps: 4-bolts splayed, stepped registers w/ ring dowels, nodular iron or billet steel
- Fuel Pump: OEM mount
- Starter: OEM mount
- Motor Mounts: Dual (front and side)
- Cylinder Head Holes: Blind tapped to prevent leaks
- Weight: Approximately 270 lbs.
- Cam Bearings: 2.120"
- Oil Restrictors: Simple npt plug drilled to desired size located in lifter valley
- Inner Lifter Valley Extra Head Bolts BMP 701302
- Dowel and Plug Kit: BMP 703892B-2K
- Rear Seal: FEL2904