Manley 11639-1 Race Master Stainless Steel Exhaust Valve Ford 4.6L 2V 37mm

The Manley 11639-1 is a single Race Master stainless steel exhaust valve engineered for Ford 4.6L and 5.4L 2-valve Performance Improved (PI) modular cylinder heads. Featuring a +1mm oversize 37mm head diameter, this valve is an ideal upgrade for engines that have had their seats cut for oversize valves, or for builders seeking improved exhaust flow over the stock valve diameter.

Key Features:

• Race Master Series: Engineered to meet the demands of bracket, drag, and oval track racing applications operating under 8,000 RPM
• Stainless Steel Construction: Exhaust valve crafted from XH-426 high-quality stainless steel for superior durability and heat resistance
• Chrome Stem: Hard chrome-plated stem provides exceptional wear resistance and longevity against valve guide surfaces
• Swirl-Polished Under Head: Swirl polished under-head area and fully machined combustion face optimize exhaust gas flow and combustion efficiency
• Hardened Tip: Fully hardened valve tip withstands repeated contact with rocker arms and eliminates premature tip wear
• Closely Controlled Tolerances: Exact stem-to-seat concentricity ensures a reliable, consistent seal every time
• Head Diameter: 37mm (+1mm Oversize)
• Stem Diameter: 0.274 in.
• Overall Length: 4.650 in. (118.11mm)

Sold individually (single valve). This valve is compatible with standard single-groove valve locks. For builds requiring Manley's Bead Loc® keeper groove, see part number 11639B-1. Manley Race Master valves deliver the precise tolerances and durable materials demanded by performance engine builders building reliable, high-output Ford modular engines.