GJYSYP Oil Block Off Plugs for GM LSX/LT Non-AFM Engines — 8-Pack Stainless Steel, Fits 4.8–6.2L (2008–2023)

GJYSYP oil block off plugs are precision-fit stainless steel seals designed to close AFM/DOD oil passages on non-AFM GM LSX and LT series 4.8L–6.2L engines (2008–2023), supplied as an 8-pack for valley sealing.

These valley seal plugs fit many LSX (LS1, LS2, LS3, LS7, etc.) and LT (LT1, LT4, LT5, etc.) non-AFM GM engines with displacements of 4.8, 5.3, 6.0, and 6.2 liters made between 2008 and 2023. Machined from stainless steel and finished with corrosion-resistant treatment, each plug installs by gently tapping into the oil passage so the head sits flush; the top contains a 4 mm x 0.7 threaded hole for straightforward removal if needed. The set includes eight plugs, enough to seal typical valley AFM/DOD ports when converting or servicing engines.

How do these plugs install into the engine valley?

Installation is mechanical and requires no adhesive: align the plug with the AFM oil passage and gently tap it into place until the head sits flush with the bottom edge of the bung. For a tight fit that occasionally resists seating, chilling the plug (e.g., brief freezing) can reduce its diameter slightly and ease insertion. If removal is necessary, use a 4 mm x 0.7 threaded tool to back the plug out safely.

• Tap-in installation—no sealant required under normal conditions
• Flush-mounted head for a clean valley surface
• Top threaded hole (4 mm x 0.7) for removal using a matching extractor
• Freezing recommended if plug will not press-fit initially

Which engines and displacements are these compatible with?

These plugs are manufactured to fit non-AFM GM LSX and LT series engines from model years 2008–2023 and support common displacements including 4.8L, 5.3L, 6.0L, and 6.2L. They are intended to seal AFM/DOD oil passages typically found under the valvetrain lifter oil manifold (VLOM) plate on non-AFM variants. Always verify port counts and bore size against your engine prior to purchase.

• Fits LSX (LS1, LS2, LS3, LS7, etc.) non-AFM engines
• Fits LT series (LT1, LT4, LT5, etc.) non-AFM engines
• Supports 4.8L, 5.3L, 6.0L, and 6.2L displacement configurations
• Sold as an 8-pack for typical valley sealing needs

What materials and durability features do these plugs offer?

The plugs are made from precision-machined stainless steel with an anti-corrosion surface treatment to resist environmental exposure inside the valley. Their tight tolerances are intended to maintain oil circuit integrity and provide a durable mechanical seal. GJYSYP performs quality inspections and backs the product with after-sales support for fitment or workmanship concerns.

• Stainless steel core for strength and longevity
• Surface anti-corrosion finish to reduce oxidation
• Precision machining for consistent press-fit sealing
• Manufacturer warranty and customer support from GJYSYP

Will these plugs interfere with future service or reversibility?

No permanent modification is required; plugs are removable through the supplied top threaded access and can be extracted using a compatible 4 mm x 0.7 threaded tool. That design lets you restore factory plumbing or perform maintenance without destructive removal. Always follow service procedures and torque/cleaning guidelines when reassembling the valley area.

• Removable via 4 mm x 0.7 threaded access hole
• Non-permanent press-fit installation preserves cylinder block integrity
• Designed for serviceability and reversibility
• Recommended inspection during future valve train work

Who is this for? These GJYSYP oil block off plugs are aimed at mechanics, engine builders, and vehicle owners working on non-AFM GM LSX and LT series small-blocks who need a reliable way to seal AFM/DOD oil passages in 4.8L–6.2L engines. They suit engine conversions, valley-plugging for durability or compatibility reasons, and shop technicians who want a removable, corrosion-resistant plug solution backed by manufacturer support.