Check the listing for details. Chevy BBC 454 Rocker Stud Girdle Kit Red With 7/16" Polylock Nuts. Condition: New. Listed at 155.79 USD. PCE259.1017.01 Brand: PCE Part Number: PCE259.1017 Part Type: Rocker Arm Stud Girdles Stud Girdle Attachment Style: Clamp-on Rocker Arm Nuts Included: Yes Rocker Arm Nut Thread Size: 7/16-20 in. Rocker Arm Nut Style: Polylock Minimum Rocker Slot Width (in): 0.600 in. Tall-Style Valve Covers Required: Yes Stud Girdle Material: Aluminum Stud Girdle Finish: Red anodized Quantity: Sold as a kit. These CNC-machined PCEstud girdles help control valve lift and timing changes due to stud flex, allowing for more consistent high-rpm performance. Each stud girdle is anodized and comes with high-quality mounting hardware and hardened adjusting nuts. Tall-style valve covers are required. The best thing you will ever do for your engine is to put a set of stud girdles on it. This stabilizes the valve train, and allows for full lift. Studs will flex on an engine at high rpm, when running cams that are higher than stock, and those running roller cams with higher spring pressures, must have these. We never build an engine without installing a set of these. Takes no additional time to install than when installing roller rockers. It's an absolute fact that studs will flex at mid to high rpm. It happens in an erratic fashion, causing loss of engine smoothness, hp, and slower acceleration. For the low cost, we have them for these are a must. Besides gaining 5-10 hp o Item Condition: Brand New AT RACING WORLD - AUTO PARTS & CAR CARE We Mean Business when it comes to getting you the Products and Customer Service you need... when you need them. In today's extremely agressive marketplace, all companies face the issues of global competition and the ever increasing costs of operating a business environment. We created a low-overhead business model and an extremely efficient global supply chain, providing our customers with high-quality products at extremely low prices.