The IAG Trojan Short Block starts with brand new Subaru 2.5L engine case halves. IAG machines the case halves assembled together in our Haas VF-4SS CNC mill to accept the IAG CLOSED Deck Inserts that transform the block into a solid deck. The unique inserts feature small passages that allow needed coolant flow to the deck surface. The case halves are then CNC machined with O-ring receiver grooves around the bore surface as well as drilled and tapped to accept 1/2" head studs that greatly reduce head gasket failure during high cylinder pressure scenarios. Next, the short block is Deck Plate bored and honed to 99.75mm in our in-house Sunnen SV-30 the most advanced automotive cylinder hone available. IAG‘s in-house honing process is able to set custom piston to wall clearances to best fit your needs. The modified case halves are then assembled using a new 2017+ Subaru 2.5L nitride treated STI crankshaft that is matched to ACL or King race main bearings. IAG-Spec Tuff H-Beam connecting rods and ARP 625+ rod bolts are utilized along with ACL or King race rod bearings. The case halves are sealed with new OEM main/case bolts and sealant. Finally, IAG-Spec 99.75mm JE FSR 2618 Forged Pistons and electroless nickel plated tops and ring area as well as upgraded .250" / .906" H13 wrist pins are added to finish the Trojan short block. Additionally, all IAG-Spec piston skirts utilize the JE Perfect Skirt coating.
IAG Trojan Closed Deck Includes:
- Case Halves - Converted to Closed Deck using brand new Subaru OEM case halves, bored and honed to 99.75mm.
- O-Ringing - Machine and O-Ring Deck Surface
- Head Studs - Machine Case to 1/2" 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 / 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.
Additional Options Available:
- Head Studs - IAG 1/2" ARP Head Stud Set - $499.99
- Oil Pump - Subaru JDM 12mm High Volume Oil Pump - $219 or 11mm Subaru Oil Pump - $199.95
- Head Gaskets - JE Pro Seal .039 inch Head Gaskets (PN# SB1001-039 for D25 & B25 Heads, PN# SB1003-039 for V25, W25 & N25 Heads)
- IAG Oil Pickup - Upgraded oil pickup featuring heavy gauge steel tubing, 2 point bracket & mesh filter - $129.99
- Hardware / Seal Option - $105.99 (Wrist pin plugs, washers, separator cover, bolts, etc. In case you don’t want to transfer from the original engine).
- 8.5:1 on D Cylinder Heads (EJ255)
- 8.2:1 on B, V and W EJ257 Heads with standard thickness gasket.
Head Gasket Recommendations:
- *IAG Recommends JE Pro Seal .039 inch head gaskets
- JE PN# SB1001-039 are for use with S20, B25 & D25 Cylinder Head Castings (04-06 STI, 06-14 WRX, 04-13 FXT, 05-12 LGT, 02-05 WRX)
- JE PN# SB1003-039 are for use with V25, W25 & N25 Cylinder Head Casting (2007-19 STI)
The IAG Trojan Short Block has a power output rating of 750BHP.
2002-2005 WRX Require Mods
2005-2009 Legacy GT
2004-2013 Forester XT
*All IAG short blocks are balanced and blueprinted.
*Pictures used for marketing purposes only, actual product may vary
Returns may be accepted within 14 days of purchase pending Return Merchandise Authorization (RMA). No returns or cancellations on special order items. All returns will be charged a 20% restocking fee, no exceptions.
To be eligible for a return, your item must be unused and in the same condition that you received it. It must also be in the original packaging. Item must be able to be resold as new. Several types of goods are exempt from being returned. Hazardous materials, fluids, greases, chemicals, and clothing are not able to return.
Free shipping is available within the lower 48 states for most orders totaling $199 or more. A free shipping option will be available during checkout. This offer is for delivery address in the continental United States and excludes shipments going to Alaska, Hawaii, Military Boxes, and items that require freight shipping.
Patterson Performance stocks a large quantity of items at any given time. Some items may require drop shipping from one of our various distributors. In stock items will ship within 1-2 business days. If you're needing your product quickly, please contact us to verify product availability before placing your order. Orders requiring additional verification (security concerns, incorrect information, etc.) may need additional processing time. Estimated shipping dates are not guaranteed and are subject to change based on inventory levels and manufacturer lead times. Backordered items are shipped immediately once available.
Items ship daily, If the item you ordered is not in stock, a member of our team will contact you via email / phone.
Patterson Performance will only ship to an address that varies from your billing address if payment is made via Paypal or a financing partner.
Patterson Performance ships from multiple warehouses throughout the United States, and sometimes from manufacturers overseas.
You can simply contact us via email / telephone for a live inventory check
Find more information at www.P65Warnings.ca.gov.