Melling Performance has released two new all-in-one Active Fuel Management (AFM) delete kits for GM 5.3-liter engines. For LS engines, the MDK300-HPT targets the LC9, LH6, LMG, and LY5 engine codes. For LT engines, the MDK400-HPT covers the L82, L83, and L8B variants. Both kits earned SEMA Emissions Certification for 2026. Additionally, both took home the 2025 SEMA Media’s Choice Award. That recognition puts them among the most talked-about new AFM delete products on the market.
AFM has long been a headache for 5.3-liter owners. General Motors built the system to improve fuel economy by deactivating cylinders under light load. However, it carries a well-documented history of premature lifter failures. That failure rate has pushed many owners and shops toward AFM delete solutions. Melling’s MDK300-HPT and MDK400-HPT kits tackle that problem head-on with a complete, all-in-one approach.
What’s Inside the Kit
Featuring Melling engine components, each kit includes a billet steel camshaft, OEM non-AFM roller lifters, non-AFM lifter guide plates, a camshaft thrust plate, and a VVT solenoid bolt. Bundling these parts together removes the need to source components individually. As a result, installers get confirmed compatibility across the entire assembly. Melling created this kit so builders would have everything in one box. That approach is especially useful for shops doing back-to-back AFM conversions.
App-Driven AFM Disable
One of the standout features on both kits is the app-driven programming interface. Instead of needing a dedicated tuning device, installers can disable AFM straight from a smartphone. Additionally, the programming interface will act as a complete scan tool that allows users to monitor data, read diagnostic codes, and clear diagnostic codes. That convenience saves real time for shops and builders handling these conversions regularly. Furthermore, it lowers the barrier for owners who want a straightforward path to eliminating AFM without complex equipment.
Overall, the MDK300-HPT and MDK400-HPT offer a clean answer to one of the most common 5.3-liter complaints. Melling already secured SEMA Emissions Certification for 2026, making the kits compliant in 49 states. Moreover, the 2025 SEMA Media’s Choice Award adds further credibility to the product. For shops and enthusiasts ready to put AFM failures behind them, these kits cover it all from the camshaft up.
You might also like
LS-Swapped Airplane Takes Flight With Corvette LS3 Power
An LS-swapped airplane powered by a Corvette LS3 shows how GM’s small-block V8 can take experimental aviation to new heights.
