Proform Heavy, Medium, and Light Springs Included BB1901 1977-gmc-g35-esi7900123 working equally well with Speed

working equally well with Speed Engineering headers or factory exhaust manifolds

2006 thru 2016 Engines Description_LAB Engine Lift Plate Description_LAB Steel Description_LAB Fits GM LS Gen IV

Race version — no air or EGR fittings

Ships unwelded for custom fitment

Deep Blk Suede/ Neon Green Stitch w/5mm Matte Black Spoke

Proform Heavy, Medium, and Light Springs Included BB1901 1977-gmc-g35-esi7900123 working equally well with SpeedWhen accuracy is the difference between winning and losing, there's one test spring kit that's a cut above the rest the RIMAC calibrated 3 in 1 test spring kit. This spring kit include three test springs: a lightweight spring, a medium weight, and a combined heavy weight spring giving you an approximate test range from 10 640 lbs. Data sheet included. Super accurate and individually tested on an Instron SF1240 testing machine. Proform Heavy, Medium,