Top Categories
All Categories

Top Categories

All Categories

Shop By Vehicle
Account Login
Gift Cards
Track Order
World Products 081111

World Products Merlin III Mark-IV Cast Iron Engine Block BB Chevy


made in usa
Ships directly from the manufacturer on 09/25/19
Save $20 Off $250, $50 Off $500, $100 Off $1,000, $150 Off $2,000. Promo Code: SAVEMORE exclusions apply

Truck Freight:$159.00
World Products Merlin III Mark-IV Cast Iron Engine Block BB Chevy $2,367.51
Out of stock
Merlin III Mark-IV Cast Iron Engine Block
  • Big Block Chevy
  • 2-Piece Rear Main Seal
  • 4.495'' Bore
  • 10.200'' Deck Height
  • Nodular Iron Main Caps
  • Specifications:

    Manufacturer's Part Number:

    Perfect Foundation for Any Big Block Chevy Build!

    Ideal for street, ET bracket racing, and marine applications, World Products applied almost 15 years of Merlin knowledge to develop these blocks, offered bare or race-prepped. The race version features a thoroughly-washed block, plate-honed cylinders to the bore size, and installed cam bearings and freeze plugs. Merlin III blocks have reinforced bulkheads and main webs, thicker decks, 100% compatibility with Mark IV components, and indexed lifter bores for optimum reliabilty. Their quality is superior to OE parts, especially because each block is CNC-machined to QS-9000 specs using only two fixturing operations (thus avoiding tolerance stacking common to factory blocks from assembly lines). Cylinder bore sizes are standard, with bores semi-finished to allow final honing to suit your specific piston and ring package. Race prepped blocks are finished honed to an exact 4.500'' bore. Made In The USA!

    Merlin III Mark IV-style big block is a two-piece rear main seal and compatible with all original GM Mark IV pieces and components including fuel pump, starter, oil filter, and cylinder heads.
    Merlin III Gen VI-style big block features a one-piece rear main seal and a Gen VI-style oil pan rail and front cover bolt pattern. The block can utilize either the OE type roller lifters or +.300'' tall tie bar lifters. It also features a Mark IV style fuel pump boss and oil filter pad. The water jacket and surface will accommodate either Mark IV or Gen V-VI style cylinder heads, making this block extremely versatile.


    • Material: Cast Iron
    • Bore: Semi-finished to allow final honing to piston/ring package; Race-prepped block is finish honed
    • Deck Height: 9.800'' (std) or 10.200'' (tall)
    • Deck Thickness: .600'' Minimum
    • Cam Bearings: Standard Chevy
    • Main Bearings: Standard Chevy
    • Camshaft Location: Stock
    • Lifter Bores: Indexed
    • Maximum Recommended Bore: 4.625''
    • Cylinder Wall Thickness: .250'' @ 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 (can be clearanced for Strokers)
    • Oil System Features:Stepped oilingDry sump systems can feed from front or rearOil drainback in valley lubricates distributor gearDrilled for dry sump valley scavenge linesExtra head bolt bosses in valley to accommodate special racing headsBlind holes drilled into valley for screen
    • Crank Clearance: 4.375'' for 9.800'' deck or 4.750'' for 10.200'' deck
    • Main Caps: 4-bolt nodular iron or splayed billet steel
    • Rear Main: Mark IV 2-piece seal; Gen VI 1-piece seal
    • Fuel Pump Mount: OE mount
    • Starter: OE mount
    • Motor Mounts: Front and side
    • Cylinder Head Holes: Blind tapped to prevent leaks
    • Weight: Approximately 270 lbs
    • Made In The USA

    Items You Need

    Some parts are not legal for use in California or other states with similar laws / regulations

    Motor Vehicles

    WARNING: Motor vehicles contain fuel, oils and fluids, battery posts, terminals and related accessories which contain lead and lead compounds and other chemicals known to the State of California to cause cancer, birth defects and other reproductive harm. These chemicals are found in vehicles, vehicle parts and accessories, both new and as replacements. When being serviced, these vehicles generate used oil, waste fluids, grease, fumes and particulates, all known to the State of California to cause cancer, birth defects, and reproductive harm.


    WARNING: Some dust created by power sanding, sawing, grinding, drilling, and other construction activities contains chemicals known to the State of California to cause cancer and birth defects or other reproductive harm. Some examples of these chemicals are: lead from lead-based paints, crystalline silica from bricks and cement and other masonry products, and arsenic and chromium from chemically treated lumber. Your risk from exposure to these chemicals varies, depending on how often you do this type of work. To reduce your exposure, work in a well-ventilated area and with approved safety equipment, such as dust masks that are specially designed to filter out microscopic particles.

    Electrical Cords

    WARNING: The wires of these products contain chemicals known to the State of California to cause cancer and birth defects or other reproductive harm. Wash hands after handling.