IAG Stage 3 Pocket Ported Heads w/ +1mm GSC Valves for 08-17 STI W25 Casting (Cams / Lifters Sold Separately). 2011-subaru-impreza-wrx The IAG Stage 2 pocket

The IAG Stage 2 pocket ported head package starts with brand new WRX STI OEM V25 head castings

Each package starts with brand new WRX STI N25 OEM head castings

The ported head package starts with brand new WRX STI OEM N25 head castings directly from Subaru of America

Then 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

Short after the heads are drilled to fit larger 1/2" or 14mm head studs which are commonly used in high horsepower builds

IAG Stage 3 Pocket Ported Heads w/ +1mm GSC Valves for 08-17 STI W25 Casting (Cams / Lifters Sold Separately). 2011-subaru-impreza-wrx The IAG Stage 2 pocketIAG Stage 3 Pocket Port Cylinder Head Package: The head package centers around our popular CNC pocket porting program which was developed over the last several years. Pocket porting removes excess OEM casting flash and the material underneath the valves. By smoothing and blending this area under the valve seat, significant flow capability can be achieved. The IAG Stage 3 pocket ported head package starts with brand new WRX STI OEM W25 head castings,