THIS IS ONE OF THE HEAVIEST VALVE SPRING KITS FOR AGRESSIVE HIGH LIFT LS CAMS FOR HEADS LIMITED BY THE STOCK DIAMETER 1.290-1.320 OD VALVE SPRINGS. IT IS RECOMMEND THIS KIT BE USED WITH SHORT TRAVEL HYDRAULIC RACE LIFTER (CONTACT ZL1 SPEED SHOP FOR CORRECT LIFTER) TO REDUCE RISK OF PREMATURE VALVE TRAIN FAILURE. FURTHERMORE, WE OFFER A 1207X KIT THAT MAY BE BETTER FOR STOCK HEADS WITH STANDARD VALVE SEATS AND POWERED METAL VALVE GUIDES. WE NORMALLY USE THE 1208 ON BRODIX HEADS WITH HARDENED SEATS AND HIGH QUALITY BRONZE GUIDES AND THE 1207X KIT THAT HAS SLIGHTLY LESS PRESSURE ON STOCK GM CASTINGS. REGARDLESS UPGRADED REDUCED TO SHORT TRAVEL LIFTERS ARE RECOMMENDED WITH EITHER THE 1207 OR 1208 KIT ALONG WITH UPGRADED THICK WALL PUSH RODS. THIS SPRING CAN BE USED TO .760 LIFT WITH CORRECT INSTALLED HEIGHT DEPENDING ON WEIGHT OF VALVE AND OTHER VALVE TRAIN COMPONENTS. LARGER END RADIUS ON PUSH ROD MAY BE REQUIRED DEPENDING ON TYPE OF ROCKER ARM USED AND LOBE LIFT OF CAMSHAFT. CONTACT THE ZL1 SPEED SHOP FOR GUIDENCE ON A WINNING COMBINATION OF PARTS TO COMPLEMENT THIS SPRING KIT--WE HAVE PROVEN OUR COMPONENT SELECTION ON MORE THAN 50 ENGINES IN THE PAST FEW YEARS TO 1500HP LEVELS USING THIS SPRING KIT.  WE CAN OFFER YOU A CUSTOM BUILT SET OF CUSTOM HEADS WITH SPECIAL FEUATURES SUCH AS HOLLOW STEM AND/ OR INCONEL EXHAUST VALVES, SEMI PORTED OR FULLY PORTED AND CUSTOM CAM AND LIFTER AND PUSH ROD PACKAGES. 20+ YEARS EXPERIENCE IN CAMSHAFT AND HEAD R & D. BUY WITH CONFIDENCE!

Be sure to leave note at check out if you want .505  stock spring seats or .565 seat. Also, we different seals for bronze guides vs stock guides. Contact us for additional infomation.

This spring kit contains PAC 1208X Dual Valve Springs, matching titanium retainers, your choice of locators for stock or bronze guides, locks, and seals.

Spring Specs are 160 lbs @ 1.800", 482 lbs @ 1.100", Coil Bind 1.000", Max Lift .750"

This is a drop in spring kit for all 12- 15 degree LS heads including: LS1, LS2, LS3, LS4, LS6, L76, L92, L99, LQ4, LQ9, L33, LSA...etc.  This kit will not fit LS9 engines.  It will fit LS7 heads.