We are pleased to announce the release of our second generation Stage 2 2.5L Short Block. The GS650 exemplifies all of our experience building and tuning high horsepower race and street engines. The GS650 has been installed on daily-driven cars that make over 600HP on the street, safely and reliably. These are the same cars that drive to the track, run sub-11 second times and are driven home. This block is capable of maxing out the GT35R turbo (ask MARKGSTI
The GS650 starts life as a regular STI shortblock. First we replace the weak hyper-cast stock pistons with custom spec forged units (coated). Not only are the pistons significantly stronger than the stock units the pistons are substantially lighter too. We then address the connecting rods. The rods are replaced with Helix forged H-beam rods held together with ARP L-19 bolts. The super-strong forged rods coupled with the best rod bolts available on the market allow for high RPM operation. The crankshaft is then modified with our proprietary techniques creating a crankshaft similar to the $2000 STI race crankshaft used on the WRC cars. The bearings are swapped out in favor of Gruppe-S coated race bearings. This addresses all the common main failure points of the stock STI 2.5 engine – spun bearings, cracked pistons, and damaged rods.
The entire assembly is then balanced. Piston walls are bored and honed, all tolerances are triple checked, and the assembly is professionally assembled. The end result is a big power engine that is capable of 8500 RPM operation* and holding 650 crank HP. That’s right, 165 HP PER A CYLINDER. The GS650 is purposely built to tight tolerances for street operation. You will not experience excessive oil consumption and you will not have a rocking issue with our pistons.
-30psi boost limit
-650HP reliable horsepower limit
*”Looser” race engines (not recommended for street use) are available – simply let us know if that is what you are looking for.
**8500 RPM requires substantial modifications to the head, oiling system, and other components. We have experience building high revving engines, please contact us for additional details.
-Gruppe-S / Wiseco Forged and Coated Pistons
-Coated High Performance Rod & Crankshaft bearings
-Reworked Forged STi Crankshaft
-Helix Forged H-beam Connecting Rods w/ ARP L19 bolts
-Professionally balanced and assembled (recommended 7500 RPM redline)
-Rehoned cylinder walls
-Capable of up to 650 CHP Operation
-Final Displacement 2.48L
-Compression ~8.5 : 1
Gruppe Buy Price: $3299
Price with 2.5L block trade in (must be functional and in good shape) - $2699
Phone: (510) 783-5300
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