GSC S1, S2 and S3 billet camshafts are available for 1G/2G DSM builds from basic bolt-on's to 800+ HP. These cams are sold as the pair, both intake and exhaust for the 4G63 engine. Please review all options below and if you need any help, just give us a call.Vehicle Fitment:4G63 1G/2G DSM1990-1999 Eclipse GST/GSX1990-1998 Talon TSi1990-1994 Laser RS1991-1992 Galant VR41992-1995 Evo 1-37003S1 S1 Cams (268/268)The S1 cams are designed for those running a small 16G or large 16G turbo. These cams will not sacrifice any bottom end loss over stock cams; nothing but gains and will promote faster spooling of the turbo. Gains of 15-25whp (depending on Turbo) have been seen by simply bolting the S1 cams in. Designed for a rev range of 3000-8000rpms, these cams work well on the stock valve springs.• 250-400whp camshaft.• Idle is slightly rougher than stock7003S2 S2 Cams (274/274)The S2 cams are designed for those running larger turbo's 61mm and larger.Gains of 30-65whp (depending on Turbo) have been seen by simply bolting the S2 cams in. Designed for a rev range of 4000-9000rpms, upgraded valve springs strongly suggested.• 450-800whp camshaft.• Idle is rougher than stock.7003S3 S3 Cams (280/280)The Billet S3 cams are designed for those running larger turbo's 67mm and larger. Designed for a rev range of 4500-9500rpms, GSC Beehive Spring and retainer kit strongly suggested.• 600-1000whp camshaft.• Idle is rougher than stock.More from GSC:GSC's 7000 Series Billet Cams start off as cold-forged alloy steel bars. This means the steel is pressed into its round bar shape rather than molten steel being poured into a mold, as in cast steel cores. The benefit is that the material is both stronger and more dense, leaving no room for pores or imperfections during the forming of the core. These new cores set the base for a stronger building block in their advanced camshaft development and design process. Furthermore, on high torsion and shock load camshafts with variable valve timing, the billet cores will provide an extremely high level of reliability over the cast core camshafts.Shear stresses at all undercuts for oil routing journals are met by the stronger cross- sectional area of the billet core vs. the cast core. Shearing at any of these points in variable valve timing equipped engines is now highly unlikely. The fully turned, ground, billet camshafts are also extremely balanced in order to minimize and/or eliminate all types of added harmonics and vibrations.GSC's Nitride Coating treatment process offers the new billet camshafts a protective layer and case hardened shell to help aid in strength as well as lobe surface lubrication. This is extremely important for flat tappet style engines (IE Subaru EJ, Mitsubishi 4b11, Toyota 2JZ, etc). This nitrided layer also adds greater protection for break-in and long-term surface durability.GSC Power Division has instituted this coating across our entire product line with extreme attention to the Subaru EJ motor due to its horizontal design and the tough oiling conditions inside of the heads to the camshafts and translating tappets. GSC Power-Division is excited to see the new, higher standard of expectation these camshafts will take to the aftermarket. See more GSC Products