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Essential Iag 950 Ej25 Closed Deck Case Series [wKGzSpb1]

$123.99 $396.99 -69%

It's no secret that the OEM Subaru case halves, or "block," aren't exactly the strongest. IAG has developed a process to greatly improve the strength of the OEM Subaru EJ25 Case Halves to combat the effects of high cylinder pressures brought on by in

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It's no secret that the OEM Subaru case halves, or "block," aren't exactly the strongest. IAG has developed a process to greatly improve the strength of the OEM Subaru EJ25 Case Halves to combat the effects of high cylinder pressures brought on by increased power and boost. Our proprietary "Closed Deck" System works by supporting the top of the cylinder in the weakest areas and prevents movement and expansion which can lead to cracks and failures. Despite the additional material supporting the cylinder walls, there is no concerns with overheating or coolant flow because the area around the middle of the cylinder still maintains the same coolant area. The custom IAG closed deck inserts are machined with holes for oil and coolant to pass through the same as stock. The IAG 950 Closed Deck Case takes the strength one step further by adding provisions for our race-proven Fire-Lock™ head gaskets system, along with modifications for 14mm head studs. If you're one of those people who prefer to do your own builds we now offer our legendary closed deck case halves for purchase separately. Simply install your crank, rods, and pistons to your own specifications and be confident that the case halves will take the power and prevent common cylinder wall failures. The IAG Closed Deck conversion is performed 100% in-house by our engineers and experts using state-of-the-art equipment. The IAG Closed Deck starts with a new OEM EJ25 bare case. The case is loaded and fixtured to a 4th axis rotary indexer in our Haas VF4-SS CNC Vertical Machining Center. It is supported by the main journals using a precision ground 2-inch bar and tailstock which ensures the datum is the main journals. This method gives us a true reference point to perform all machining operations. A Rennishaw probe is utilized to check that the case is fixtured true, and once confirmed the machining process begins.

Essential Iag 950 Ej25 Closed Deck Case Series [wKGzSpb1] Includes: (x1) IAG 950 Closed Deck Converted Case Halves (99.75mm Bore and hone additional and required before final assembly!), (x1) Machined for OEM 14mm Head Studs (Head Studs Sold Separately), (x1) Machined for Fire-Lock™ Head Gaskets (Gaskets Sold Separately).
,YOU MUST PURCHASE OR SEND IN YOUR PISTONS FOR MEASUREMENT AND SIZING IF YOU SELECT THE BORE AND HONE OPTION.
,Please Note: Overbore must be performed (99.75mm is the preferred bore) before assembly!
,Head Gasket Required: IAG Fire-Lock .051" Head Gaskets with IAG-Spec Alloy Ring Set. PN# IAG-ENG-1740
,Attention: Special note about using ARP Case Bolts - IAG recommends line honing the case when using ARP Case Bolts to remove any distortion created by the hardware. IAG installs ARP CASE BOLTS with 30W engine oil using OEM SUBARU torque specs and procedures. Other torque specs and lubricants may lead to case distortion damage.

What Our Customers Say

January 11, 2026

Absolutely no complaints!

I'm happy with my product and its entire, whole, great, great, great purchase.

- Ysbaddaden H..

January 11, 2026

Absolutely no complaints!

I'm happy with this product. It is so very, so nice.

- Caswallon F..

January 11, 2026

Absolutely no complaints!

A great item. I have no complaints at all, at all, at all, at all, at all.

- Taliesin E..

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