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Jeep AMC 258 Cu. In./4.2 Liter 6 Cylinder Valve Cover

Part Number 8656

PML Jeep Valve Cover, As-Cast Finish PML Jeep Valve Cover, Black Powder Coated

This PML Jeep valve cover benefits over stock valve covers:

  • Improved baffling
  • Strong sand cast aluminum construction
  • Custom look
As-cast finish
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Black powder coating
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Dimensions: The cover has approximately 3.7 inches from the gasket to the inside top surface. Other dimensions not available.

Finishes: Read about finishes and construction of PML parts.

Installation Instructions: PML Jeep 258 Valve Cover Installation Instructions.

PML designed our valve cover for the AMC 258 (4.2 liter) straight 6 engine based on the original valve cover as it came from the factory. We use sand-cast aluminum construction to provide strength and durability and a cast-in baffling system. The gasket flange is precision-machined and 0.200-inch thick for a uniform clamping force on the gasket.

The cover includes a billet oil fill cap for a secure seal and features holes for PCV and breather. The AMC Jeep 4.2 Liter/258 cubic inch engine comes in four possible fastener configurations. The PML valve cover works with all possibilities and has provisions for the use of studded bridges and head bolts. Holes can be easily drilled for studded rocker arm bridges. Reference the Installation Instructions.

PML Jeep Valve Cover Baffles

PML's baffling system allows the engine to breath better then most. We have some street applications that do not run any breathers on our covers, and there is no blow by. This baffling system works very well as compared to others since we run along the side wall and pick up lower than most.

Blow-by is not a situation that any valve cover can stop. PML's Jeep valve cover can reduce the oil mist somewhat since the design is longer and there is a elbow that will usually separate the oil from the air, allowing it to drip down. The baffling is an integral part of the casting so there are no rivets or screws to vibrate loose.


Note: If your head has been modified (for example, the locator dowel pin holes have been drilled and tapped), our cover will not work for you.

The 258 engine was commonly used in 1971 to 1990 Jeep, AMC, Scout and some industrial vehicles.

This valve cover fits 1981 to 1986 heads.

This valve cover also fits 1987 to 1990 heads if your engine came with the plastic valve cover. If your 1987-1990 engine came with an aluminum valve cover from the factory, our valve cover will not fit your head. Engines with the aluminum valve cover have the same gasket shape and bolt pattern as the 4.0 heads. Look at the Installation Instructions for a view of the gasket shape and bolt pattern on this valve cover and verify it is the same as the valve cover you have.

1980 and earlier heads generally have a different bolt hole pattern so this PML valve cover will not fit.

This valve cover has been installed on CJs, Wagoneers, Wranglers, Eagles, and an AM General Ice Cream Truck.

Configurations vary. Always check your engine before ordering.

AMC Jeep 258 stock valve cover

Stock Cover

This is one of the stock OEM covers we used for development. The valve covers is from a 1986 Jeep CJ–7.

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1986 CJ–7

PML Jeep Valve Cover, installed   PML Jeep Valve Cover, installed, driver's side   PML Jeep Valve Cover, installed
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1985 AMC Eagle

Matthew installed this PML valve cover on his 1985 AMC Eagle 6 cylinder. He said it made a "world of difference" going from the plastic cover to the PML cover.

1985 AMC Eagle Wagon   1985 AMC Eagle Wagon 6 cylinder engine   1985 AMC Eagle Wagon with PML valve cover
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1983 AMC Eagle

Walter installed this PML valve cover on his 1983 AMC Eagle Wagon 4x4 with 258 engine (4.2L). He email us images of his installation process. Our thanks to Walter for his careful picture taking during his installation. He also installed new rocker arm bridges when he replaced his valve cover.

1983 AMC Eagle 1983 AMC Eagle 4x4 258   PML valve coverse on 1983 Eagle PML valve cover on 1983 Eagle 285 motor   Stock valve covers on a 1983 Eagle Stock valve covers of a 1983 AMC Eagle   258 Rocker arm bridges Replacing rocker arm bridges in 1983 AMC Eagle 4.2L/258 motor
258 engine nut 4.2L/258 flare nut   258 pin removal with magnet Using a magnet to remove locator pin from 258 in 1983 AMC Eagle   Removing locator pin from 258 engine 4.2L/258 pin removal, 1983 AMC Eagle   Bungee cord for wires Using a bungee cord to keep wires away from valves  
258 gasket 1983 Eagle 4.2L/258 gasket   Drilling hole Drilling hole to access rear bolt   rear bolt access Accessing rear bolt of valve cover   PML Jeep 258/4.2L valve cover on 1983 AMC Jeep 258/4.2L PML valve cover on 1983 AMC Eagle  
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The above installation has not been tried or verified by PML. PML does not recommend any of the above. Information for reference only.

PML Valve Cover Features

  • Strong sand-cast aluminum construction
  • Thick side walls and gasket flanges that will not bend when bolts are tightened
  • Cast-in internal baffles
  • Mounting hardware included

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Learn more about finishes and construction of PML parts.