AG : 950 Closed Deck 2.5L Long Block Engine w/Race Heads - (EJ25)

POWER RATING

The IAG 950 Long Block has a power output rating of 950BHP.

A "DROP-IN" SOLUTION

The IAG Performance Hand-Built Subaru EJ25 Closed Deck Long Block Engine Packages are a complete, valve cover to valve cover, crate engine. These engines offer significant ease of installation for customers seeking a complete "drop-in" engine package for their WRX, STI, Forester XT or Legacy GT. The Long Blocks feature a combination of our proven IAG Performance 950 Closed Deck Short Block and IAG 950 Cylinder Head packages, along with other race-proven components to complete the assembly. When paired with our Long Block Installation Packages, you have a true plug-and-play solution to get you back on the road, FAST! All components included are BRAND NEW and there is NEVER A CORE CHARGE required.

BUILT WITH 100% NEW COMPONENTS

The IAG 950 package is ideal for clients looking for an engine package to support up to 950 BHP applications. The IAG 950 Long Block features our IAG 950 Closed Deck Short Block that utilizes a brand new EJ20 or EJ25 Subaru case that is converted to closed deck and is bored and honed to 92.5 or 99.75mm. The IAG 950 block features 14mm head stud machining, as well as our Fire-Lock™ gasket solution that is loosely derived from diesel technology where a counterbore step is machined around each cylinder bore allowing specially sized fire rings to drop into the machined area and head gasket bores. The combination of the alloy compression shims and gaskets assure maximum sealing for a Subaru EJ20 or EJ25 turbocharged engine.

The IAG 950 internals include IAG-Spec JE FSR 2618 forged pistons, .250" / .906" H13 pins, IAG-Spec Tuff H-Beam +2mm connecting rods with ARP 625+ rods bolts and an OEM STI crankshaft. The block is then paired up with our IAG 950 Fully CNC Ported Cylinder Heads to deliver maximum flow for high horsepower applications. The heads start as brand new Subaru OEM cylinder head castings that are CNC machined and resurfaced. The heads are outfitted with GSC valve train components, consisting of +1mm oversized intake and SuperAlloy exhaust valves, IAG Beehive Springs, as well as GSC Billet Stage 2 camshafts. To complete the package, we add an IAG / ARP 14mm head stud set and all the required gaskets for the final valve cover-to-valve cover assembly. 

RACE ON SUNDAY, WORK ON MONDAY

The IAG 950 Short Block is the ultimate "weekend racer" block. Built to withstand up to 950 BHP, this is our strongest "Street" short block offering. The IAG 950 short block features +2mm IAG Spec H-Beam forged connecting rods, IAG-Spec JE Pistons with electroless nickel plated coating with H13 tool steel wrist pins, and our venerable "Fire-Lock™" head gasket system for 14mm head studs. Each IAG 950 short block is hand assembled using ACL or King rod and main bearings. This combination of parts makes the IAG 950 the perfect block for drag or road racing.

BUILT WITH 100% NEW COMPONENTS

The IAG 950 Short Block starts with brand new Subaru 2.5L engine case halves. Our machinists machine the assembled case halves in our Haas VF-4SS CNC mill to accept the IAG Closed Deck inserts, transforming the block into a solid deck. Next, a deck pair of deck plates are attached and the short block is bored and honed to 99.75mm in our in-house Sunnen SV-30 computer controlled cylinder hone. IAG's in-house honing process allows us to set custom piston to wall clearances to ensure quiet operation and reduced oil consumption. The Haas mill also cuts a groove at the top of each cylinder to accept the Fire-Lock™ head gasket rings and drills each head bolt hole for 14mm head studs. The modified case halves are then assembled using a new 2017+ Subaru 2.5L nitride treated STI crankshaft and IAG-Spec Tuff H-Beam connecting rods with ARP rod bolts. IAG Short blocks feature ACL or King Race rod and main bearings and are all balanced and blueprinted. Finally, the case halves are sealed with new OEM main/case bolts and sealant.

NEVER WORRY ABOUT HEAD GASKET FAILURES

The IAG 950 EJ25 Closed Deck Short Block features our propietary "Fire-Lock™" Head gasket system. This system has been proven in our record setting race cars to be the strongest Subaru head gasket system ever produced. To achieve these results our engineers separated the combustion chamber sealing from the fluid sealing aspects of the head gaskets. Our machinists carefully machine a lip at the top of each cylinder to accept the "Fire-Lock™" ring. With the ring locked in place, it stands proud above the deck, providing a superior seal. The separate gasket bodies take care of sealing oil and coolant passges and keeping them out of the combustion chamber. 14mm Head studs (Not Included) hold the assembly together.

CLOSED DECK FOR EXTRA STRENGTH

Our unique closed deck system significantly increases the strength of the OEM case halves. This process supports the cylinder walls at the top of the case in order to prevent flexing and possible cracking where the case bolt reliefs are cut into the back of the cylinder wall.
During the installation process we machine the assembled case halves in our Haas VF-4SS CNC mill to accept the IAG Closed Deck inserts. Once the case has been machined we heat it in an oven while freezing the specially machined inserts with liquid nitrogen. The inserts are then pressed into place and then machined to a mirror finish.
The unique inserts feature small passages that allow needed coolant flow to the deck surface. This means that the closed deck system does not affect the block's cooling ability and will not cause overheating, even in daily drivers.

PISTONS SPECIALLY DESIGNED WITH POWER IN MIND

The pistons used in the IAG 950 Short Blocks are specifically designed to support the rigors of racing. Designed in partnership with JE, these IAG-Spec pistons feature electroless nickel plating and a 2618 Alloy. Extra thick ring lands resist collapsing under pressure. The upgraded .250" wall H13 tool steel offset wrist pins are designed to hold up to 950 BHP without bending or breaking. The pistons also feature JE's Perfect Skirt coating.

BUILT WITH RACING IN MIND

The IAG 950 CNC Ported Race Cylinder Heads are designed for racing and competition. These fully CNC ported heads provide a significant upgrade in flow over the IAG 750 heads. These heads work great for cars where getting more power might be the difference between winning or losing that big race. The IAG 950 heads work great for drag racing, as well as high horsepower time attack or hill climb, and are designed to support up to 950 BHP with supporting mods. These heads include upgraded GSC +1MM Superalloy Valves, GSC Viton Valve Stem Seals, Upgraded GSC Valve Guides, IAG-Spec Beehive Valve Springs with Titanium Retainers, and OEM Keepers. GSC S2 Camshafts are available with OEM valve lifter buckets. We also offer an optional chamber modification service (see below) for EJ20 heads to allow use on EJ25 short blocks.

BUILT WITH 100% NEW COMPONENTS

Each IAG 950 Cylinder Head Set starts with new OEM castings from Subaru of America. The first step is to select your Year and Model of vehicle so that we may provide you with the right castings to fit your project. Next, you'll select whether or not you want to include our optional GSC camshaft package. If selected, these heads will include new GSC S2 Camshafts and OEM Lifter Buckets for valve adjustment.

This IAG 950 fully CNC ported head package starts with brand new WRX STI OEM head castings directly from Subaru of America. The bare castings are visually inspected then fixtured into our in-house Centroid 5-axis CNC Machine. The Centroid CNC ports the intake and hard to reach exhaust "dog-leg" port runner. The benefit of CNC porting is not only an efficient way of machining the heads it also offers consistent port results that are hard to achieve by hand. Once the Centroid completes the port process the heads undergo a cam clearance machining process that removes material from the lifter area where large duration cam profiles are known to contact the castings. Shortly after the heads are drilled to fit larger 1/2" or 14mm head studs, which are commonly used in high horsepower builds.

Next, the OEM guides are pressed out and replaced in favor of GSC Manganese-Bronze valve guides that are shaped to improve airflow. Once all the new intake and exhaust guides are in place they are diamond-honed in our honing station. The heads are then fixtured in our Newen 3.0 Valve Guide and Seat Machine to cut all intake and exhaust seats with a multi-angle valve job that suits the flow characteristics of GSC's +1mm valves. At this point, the heads' decks are resurfaced using our TS-3000 BlockMate which cuts the aluminum to a smooth even finish. Next, the heads are ultrasonically cleaned to remove debris and oils from the machining process. Finally, the heads are reassembled using IAG-Spec Beehive Valve Springs and Retainers along with GSC Viton stem seals.

WHAT MAKES CNC PORTING BETTER?

Cylinder head porting has been around since the invention of the internal combustion engine. It can be done by hand with a die grinder and some cartridge rolls, and a seasoned professional can likely get a good result that way. Unfortunately, doing porting this way requires a lot of experience and care. One slip of the die grinder can ruin your cylinder head. This is where CNC porting comes in. Using our Centroid 5 axis CNC porting machine we can achieve the same results every time we put a set of heads into the machine. Every cylinder head comes out exactly the same and uses our race-proven, computer controlled, CNC porting program to guarantee results.

GSC S2 CAMSHAFT AND LIFTER BUCKET PACKAGE

To get the most out of these heads we selected the GSC Power-Division billet S2 camshafts for your IAG 950 Head Package. These cams are built to suit the higher horsepower these heads will support. With a power range of 500 WHP and up, you need some additional supporting mods to utilize the true potential of the S2s. Our IAG 950 Short Block, an upgraded turbocharger and fuel system, and a quality engine management system are key. Along with the camshafts we'll include all new OEM valve lifter buckets and set final lash. 

QUALITY GURANTEED

We stand behind every hand-built engine we produce. IAG's Standard Long Block Workmanship Warranty covers your long block for 12 months or 12,000 miles. 

IAG 950 EJ25 2.5L LONG BLOCK INCLUDES

IAG 950 Closed Deck EJ25 Short Block:

• Case Halves - Converted to Closed Deck using brand new Subaru OEM case halves, bored and honed to 99.75mm.
• Fire-Lock - IAG Fire-Lock™ receiver groove machining, latest solution to prevent head gasket failure on high horsepower and high boost Subaru's - *IAG Fire-Lock™ head gaskets required
• Head Studs - Machine Case for 14mm head studs - *Head studs are sold separately
• Pistons - IAG-Spec JE FSR 99.75mm 2618 Forged Pistons, Electroless Nickel Plated Tops & Ring area, Ring Set, .250" / .906" H13 Wrist Pins, Clips, (Perfect Skirt Coating and Offset Wrist Pins)
• Connecting Rods - IAG-Spec Tuff H-Beam +2mm / ARP 625+ Rod Bolts.
• Rod / Main Bearings - ACL or King Race bearings.
• Crankshaft - Standard New Subaru Nitride Treated 2017+ STI Crankshaft.
• Case / Main Bolts - Standard FHI Subaru case bolts.

or

IAG 950 EJ20 2.0L Closed Deck Short Block:

• • Case Halves - Converted to Closed Deck using brand new Subaru OEM case halves, bored and honed to 92.5mm.
  • Fire-Lock - IAG Fire-Lock™ receiver groove machining, latest solution to prevent head gasket failure on high horsepower and high boost Subaru's - *IAG Fire-Lock™ head gaskets required
  • Head Studs - Machine Case for 14mm head studs - *Head studs are sold separately
  • Pistons - IAG-Spec JE FSR 92.5mm 2618 Forged Pistons, Electroless Nickel Plated Tops & Ring area, Ring Set, .250" / .906" H13 Wrist Pins, Clips, (Perfect Skirt Coating and Offset Wrist Pins)
  • Connecting Rods - IAG-Spec Tuff H-Beam +2mm / ARP 625+ Rod Bolts.
  • Rod / Main Bearings - ACL or King Race bearings.
  • Crankshaft - Standard New Subaru EJ20 Crankshaft.
  • Case / Main Bolts - Standard FHI Subaru case bolts.

IAG 950 CNC Ported Cylinder Heads:

• Heads - Brand New Subaru OEM WRX STI Cylinder Head Castings
• Machine Porting - CNC Ported Intake and Exhaust Runners
• Intake Valves - GSC 37mm (+1mm) Intake Valves
• Exhaust Valves - GSC 33mm (+1mm) SuperAlloy Exhaust Valves
• Springs / Retainers - IAG-Spec Beehive Valve Springs & Retainers
• Guides - GSC Maganese Valve Guides
• Valve Seals - GSC Valve Stem Seals
• Lifters - OEM Lifter Buckets
• Camshafts - GSC Stage 2 Billet Camshafts
• Multi-Angle Valve Job
• Machined Cam Lobe Clearance
• Drilled For 14mm Heads Studs
• Resurface
• Ultrasonic Cleaning
• Final Lash

Gaskets, Hardware & Accessories:

• Head Studs - IAG / ARP 14mm Set
• Head Gaskets - IAG Fire-Lock™
• Valve Cover Gaskets - OEM
• Cam Seals - OEM
• Valve Covers - OEM
• Wrist Pin Seal, Rear Main Seal & Separator Kit
• Crankshaft Woodruff Key

Vehicle Fitment:

Additional hardware may be required to install this long block to the following vehicles, including but no limited to ECU, Sensors, Ancillaries, Covers, Pumps etc.

• 1999-2014 Subaru WRX
• 1999-2021 Subaru STI
• 1997-2013 Subaru Forester XT
• 2004-2009 Subaru Liberty GT
• 2004-2009 Subaru Outback XT