Street Spec Pro Shortblock

Our Stage 3 fully built street series shortblock supports up to 850bhp with proper tuning and supporting modifications. Our short blocks are race proven for durability and reliability. The street series is built for low noise, minimal oil consumption, and is designed to last years (not months like some of our competitors). Cosworth's specially developed alloy allows piston clearances to be kept low while the boxed-strut forging design and short pin length ensure the strength and stiffness necessary to withstand high power levels. Each short block is assembled from new parts in a dedicated clean environment by our two in-house builders with a combined Subaru race engine building experience of over 30 years.

Our Street Spec Pro is designed to support big power levels reliably. It features a fully closed deck design by utilizing cast aluminum inserts press fit into carefully machined areas of the block face to reinforce the highly stressed upper area of the cylinders as well as stabilizing the deck surface. The block is also machined to accept 14 x 2.00mm head studs (sold separately), a necessity to support extreme power outputs. The coarse 2.00mm head stud thread pitch is superior in resisting thread pull-out compared to a 1.50mm pitch. In addition we machine the block to utilize a Fire Lock head gasket (sold separately). The separate Fire Lock combustion sealing ring and its receiver groove in the block is superior in sealing extreme cylinder pressures compared to conventional head gasket designs and even the Athena cut ring head gasket. Every block is precisely diamond honed to size while fitted with torque plates to replicate the assembly distortion. A final plateau hone ensures fast and consistent ring break-in.

Every build goes through a rigorous ultrasonic cleaning, measuring, and assembly process with each measurement logged for future reference. Components are weight matched and carefully machined and polished as required to achieve the desired tolerance. Bearing clearances are measured with calibrated Mitutoyo micrometers and precision Sunnen dial bore gauges and adjusted to within +/- .00015" by substituting bearing shells. Piston ring gaps are hand filed to within .001"of the target clearance which is based on the intended use and expected power levels. Low tension rings utilizing ring gaps developed through our extensive experience ensures reduced oil consumption and blow-by while keeping ring friction to a minimum.

The components used in this short block are as follows: EJ257 Fully Closed Deck Block Cases, Cosworth Forged Pistons w/ Xylan Skirt Coating, RalliSpec PRO Series Tri-Beam 4340 Forged Rods by Saenz, ARP L19 Rod Bolts, Calico-coated ACL Tri-Metal Main Bearings, Calico-coated Clevite Rod Bearings, Nitride Hardened 79mm Crankshaft, Block Plugs & Covers Included. Machined for 14x2.00mm Head Studs and Fire Lock Head Gaskets

One year limited warranty when professionally installed and registered

Click here for shortblock comparison and specification chart.

Click here for warranty and engine break-in information.

Applications:

• Subaru WRX STI MY15-21
• Subaru Impreza STI MY01-14
• Subaru Impreza WRX MY06-14
• Subaru Legacy GT MY05-12 (IF MY10-12 YOU MUST CONTACT US)
• Subaru Outback XT MY05-09
• Subaru Forester XT MY04-13