Atomic Barra Cast Block | PRE-PRODUCTION
Engineering Overview
SPEC-DOC
**FIRST ORDERS OPEN EST. LATE MARCH - WE ARE NOT ACCEPTING CUSTOMER DEPOSITS UNTIL THEN.
THIS PAGE IS LIVE TO GET OUR CUSTOMERS UP TO SPEED ON SPECS AND PRICING ESTIMATES**
Atomic H260 Cast Iron Barra Block
The Industry-First Aftermarket Barra Casting
Please note: Information subject to update as production finalises.
The New Foundation
For decades, the limit of the Barra has been the block itself. While the factory design is good, the castings are VERY inconsistent with variation in wall thickness of up to 2mm in a single block 1000HP+ builds start to face cylinder stress and eventually cracking. Whilst this was the main thing we wanted to address, there are dozens of other smaller features that bring this block up to the Atomic standard. Based on approximately 1000 Barra builds, hundreds of dissassemblies, failures and breakages, and long living well put together recipes, we've made this block with a deep knowledge of what makes a Barra roar
This block uses "Murray's Magic Dust". The proprietary H260 Base Iron blend offers a +40% tensile strength increase over OEM grey iron. Stronger material combined with a 50% increase in min. cylinder wall thickness vs Factory, plus added ribbing and support structures, make for a far stronger and more stable block. Better ring seal, better bearing stability, better head gasket seal.
THE ATOMIC OPTION
The Atomic Cast Block is a direct OEM+ replacement that solves these issues. With a Siamese Bore design for rigidity, Stepped Cylinder Walls (min 5.5mm thickness), and a Thicker Deck, it is the ultimate foundation for everything from a reliable street car to a 2500HP+ drag weapon. If you're looking for a 1500-2000hp street car that doesn't overheat and need constant refreshes, our full water wet deck block is the foundation for your build.
Engineering Highlights
H260 "Magic" Iron
Special blend H260 base iron with proprietary additives. Offers +40% tensile strength vs OEM for extreme cylinder pressure containment, reducing twisting during launching and high torque scenarios.
Siamese Bores
Cylinders are connected (Siamese) rather than having a gap, massively increasing rigidity. Allows for consistent ring seal at high boost. 60% increase in bore thickness over factory.
Cooling System
Features a revised pump impeller cavity with added flow vane to assist coolant flow at idle. Internal cooling ribs support bores and increase surface area. "Grout Filled" and "dry deck" options available.
Priority Oiling
Revised oil gallery size and routing. Additional turbo feed outlet on exhaust side plus feed/sensor ports on intake side. Dual dipstick ready. Revised oil filter boss for easy relocation.
High Rod Clearance
Bore skirts are pre-relieved for increased stroke and aluminium rods. Accepts all OEM brackets, heads, and accessories.
Billet Main Caps
Designed to support Standard Style or Atomic Wide-Style 4140 Billet Steel caps. Threaded for M12 or M14 tool steel studs to ensure zero cap walk.
Technical Specifications
| Feature | Specification |
|---|---|
| Standard Bore Size | 92.25mm (Suits Atomic Pistons) Other sizes specify at purchase |
| Bore Range | Min: 85.0mm (12.5mm thickness) Rec: 92.3mm (5.5mm thickness) Max: 95.0mm (3.5mm thickness) |
| Min Wall Thickness | 5.5mm @ Skirt Base (vs 3.5mm OEM) Custom up to 12mm - Contact Atomic |
| Deck Height | Standard OEM Height Custom - Contact Atomic |
| Deck Thickness | 15mm (Massive increase for rigidity) |
| Pan Rail Thickness | 22mm |
| Bare Weight | 66kg (Factory = 63kg) |
| Main Stud Options | M12x1.5 (Standard) or M14x1.5 (Extreme) |
Block Tiers & Power Ratings
Street / Performance
- Rating: Guaranteed 1500HP. Rated to 2000hp.
- Cooling: Full Water Jackets with -16 ORB plugs
- Use Case: High HP Street, Roll Racing, Circuit/Endurance
Pro Drag (Filled)
- Rating: 2500HP+
- Cooling: "Part-Filled" dry-deck down or solid casting
- Use Case: Crazy Street, Roll Racing, Dedicated Drag Racing, Methanol
Comprehensive Change Log
Modifications and improvements over OEM design
Material & Strength
- Material: Proprietary H260 "Magic" Iron blend.
- Strength: +40% tensile strength increase over OEM grey iron.
- Structure: Added ribbing and support structures for load dispersion.
- Mass: 66kg Bare Weight (Heavy-duty casting).
Bore & Deck
- Bore Design: Siamese Bores (connected cylinders) for max rigidity.
- Wall Thickness: Min 5.5mm @ Skirt Base (60% increase over OEM).
- Deck Thickness: Massive 15mm thick deck surface.
- Sump Rail Thickness: 22mm without changing bolt positions.
- HG Interface: Revised head gasket interface to reduce leaks/splits (compatible with all existing gaskets).
- Fitment: Bore skirts pre-relieved for stroker/aluminium rod clearance.
- Bore Size Range: 85mm-95mm recommended limits (103.6mm bore spacing).
Structure & Cooling
- Increased Ribbing: Thickness and paths increased for stability.
- Custom Bellhousing: Patterns available upon request*.
- Enlarged Crankcase Cross Vents: For reduced pumping loss.
- Cooling: Internal cooling ribs to support bores*.
- Water Flow: Revised pump impeller cavity with added flow vane.
- -16 ORB Water Plugs: To allow for motorsport grade connections.
-
Rear Bellhousing Shape - exhaust side: has been revised to give addition space in that area
Oiling & Hardware
- Exhaust Side Port: Added specifically to make turbo oil feeds neater and easier.
- Main Gallery Ports: Additional ports added for feeds/sensors.
- Main Journal Oiling: Improved to increase flow and distribution.
- Improved Drains: Better venting for quicker drainage during acceleration.
- Filtration: Revised oil filter boss for easy relocation.
- Head Studs: Counterbored and threaded deeper. Standard M12 or Extreme M14.
- Main Caps: Supports standard and Atomic Wide-Style Billet caps*.
-
Dipstick: Dual dipstick drilled and ready (Front or Rear sump).
Whilst this list is long it is not a comprehensive list. If you are curious or concerned about a change or potential difference to the OEM block, please contact us.
*These features are available in second generation castings and will not be included initially. Early blocks can be modified easily to suit the wider main caps during future rebuilds.
