GSC Power-Division billet S1 camshafts for the Toyota Supra 2JZ-GTE. The S1 camshafts are designed for those running an upgraded single turbo larger than 57mm. These cams will not have bottom end losses over stock cams on larger turbos; nothing but gains and will promote an extremely flat torque curve.  These camshafts have proven power gains of 40-70 WHP (depending on turbo) with minimal modifications including re-shimming and mild tuning. Due to the added lift and duration these camshafts do require a single valve spring upgrade.