IAG 750 Closed Deck Long Block Engine w/ IAG 750 Heads, 2019-2021 STi

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 750 Closed Deck Short Block and IAG 750 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.
The IAG 750 Long Block package is ideal for clients looking for an engine package to support up to 750 BHP applications. The IAG 750 long block features our 750 Closed Deck Short Block that utilizes a brand new EJ25 Subaru case that is converted to closed deck and is bored and honed to 99.75mm. The IAG 750 short block internals include IAG-Spec JE FSR 2618 forged pistons, .210" 9130 pins, IAG-Spec Tuff H-Beam connecting rods with ARP 2000 rods bolts and an OEM STI crankshaft. The block is then paired up with our IAG 750 Pocket Ported Cylinder Heads to increase flow, but maintain spool. The heads start as brand new Subaru OEM cylinder head castings that are CNC machined and resurfaced. The heads are outfitted with GSC Standard Size Valves, GSC Viton Valve Stem Seals, GSC Valve Guides, IAG Stage 1 Valve Springs with Titanium Retainers, and OEM Keepers as well as GSC Billet Stage 1 camshafts. To complete the package, we add an 11mm ARP 625+ head stud set and all required gaskets for the final valve cover-to-valve cover assembly.
The IAG 750 Long Block Engines are available in two extra configurations to support 02-05 USDM WRX owners and International clients. Simply choose the EJ20 option for the 2.0L Closed Deck version of our 750 Short Block to be included in your long block. If you'd like an EJ25 2.5L Short Block to be used in your long block then choose the "Hybrid" option and your long block will be built with our EJ25 IAG 750 Short Block and Chamber Matched S20 2.0L EJ20 Cylinder heads.
The IAG 750 Short Block is designed to solve the majority of common problems which plague modified EJ25 engines, especially at higher horsepower levels. The IAG 750 short block builds off our IAG 550 block's strengths by adding our proprietary closed deck system. This system strengthens and supports the cylinder walls to prevent cracks which can occur with increased cylinder pressures. (This is the most common issue when increasing horsepower.) The IAG 750 also features 99.75mm JE Forged Pistons and IAG Spec H beam connecting rods, along with ACL or King Race bearings. These components also significantly strengthen the common failure points such as cracked ring lands and spun bearings.
The IAG 750 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 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.
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 crackin