PML made these valve covers for GM Generation II LT1 and LT4 small block engines, center bolt mounting to the cylinder head.
These applications may have Chevy small block engines with center bolt mounting and be able to use these valve covers:
- Crate engines, such as ZZ4 and Ramjet
- 1987 to 1998 Silverado, Sierra, Suburban, Tahoe
- 1987 to 1998 Corvette, Impala SS, Camaro Z28
- Mid 90s Pontiac Camaro and Firebird
Configurations vary! Always check your engine before ordering. See SPECIFICATIONS for information on fitment and PCV/oil fill and breather holes.
These valve covers are larger than stock. On many stock engines, there is a bracket close to the stock covers that will need modifying to work with these PML covers.
Dimensions: Click here for dimensions. A separate window will open and load an image.
Finishes: Read about finishes and construction of PML parts.
The valve covers feature vintage CHEVROLET lettering and fins for a classic appearance. PML made these for GM Generation II LT1 and LT4 small block engines, center bolt mounting.
Benefits:
- Traditional look
- Heavy duty sand cast aluminum construction for secure two bolt clamping on the cylinder head
- Optional PCV/Breather/Oil Fill holes on intake manifold side for a functional yet clean design
- Gasket and new mounting bolts included
- Slightly taller than stock
- CHEVROLET script used under license to PML, Inc., by General Motors
Award winning two–bolt design: These valve covers won the SEMA 2007 Global Media Award for the two bolt mounting design. Stock valve covers have four bolts holding the cover on to the engine. PML two bolt design removes the two center bolts for an attractive presentation.
Because PML valve covers have thick wall, sand cast aluminum construction, they are much stiffer than stock and need only two bolts to apply pressure evenly to the gasket. PML valve covers will not tweak, bend, twist or deform. No leaks and a great look to dress up your engine.
The CHEVROLET script and fins are cast into the cover and are raised. On powder coated parts, the powder coat is shaved off the top of the script and the fins.
Also available with CORVETTE script.
Gaskets: One set of custom cork composite gaskets included with each set of valve covers.
General Motors Trademarks are used under license to PML, Inc.
Fitment
Click here for dimensions. Use these dimensions to check if PML valve covers will fit on your engine.
PML fits each valve cover on an original cast iron cylinder head.
Click on image to view larger
These valve covers may fit differently on aluminum or aftermarket heads. Keep this information in mind:
- PML covers are slightly larger than stock.
- The extra height allows for many types roller rockers but not all.
- Check for interference. Some engines have a bracket or other parts that sit close to the stock covers. Some customers have reported modifying their alternator bracket so these covers will fit.
PML Small Block Valve Covers with Rocker Arms
PML designed small block Chevy valve covers to work with many roller rocker systems. However, our valve covers are not compatible with shaft mounted rocker arms such as T&D.
Click on image to view larger.
The T&D Machine Products Competition Rocker Arms are shown in this image. The shaft mounts are very tall, almost to the top of the rocker arms. The PML cast-in internal baffles will contact these mounts.
Any rocker system must have space between the rocker arms for the baffle webbing inside the PML valve covers to fit between the arms.
Inside of PML Valve Covers and Baffles
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Image shows inside of a valve cover. The areas next to the bolt holes are baffles for optional PCV and breathers. These are cast–in.
Optional PCV, Breather and Oil Fill Holes
Read this PDF file on oil fill, breather and PCV holes (click here).
PML small block valve covers are made without holes for PCV, oil fill or breather. PML can machine holes to your specifications.
For engines that require PCV and breather holes on the valve cover, PML designed the casting to be thicker on the intake manifold side and put baffles on the inside in two locations for holes. The top of the cover cannot be machined.
A separate oil fill hole is not needed since the PCV or push-in breather can be removed and oil added there.
Click on image to view larger.
PML uses four or five different tools on a CNC machine to create a clean, leak-free hole for PCV, breather or oil fill. Spot facing provides a smooth sealing surface for grommets.
To learn more, we have two videos.
The information is generally the same although a different PML valve cover is shown in these videos.
When ordering holes, you will need to specify the hole location. Holes can be machined on the passenger's side cover or on the driver's side cover, towards the front of the car or towards the rear. You can choose the location and type of hole needed in the shopping cart or can call to order. International customers, please email us for ordering.
Gaskets
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PML includes a set of our thick, cork composite gaskets with our valve covers. Gaskets are approximately 0.25 inches thick. We designed these for easy installation and to provide a leak proof seal. For additional gaskets, see Gasket for Chevy Small Block Valve Covers, Center Bolt.
Depending on the engine configuration, using less thick gaskets or gaskets made from other materials may cause installation problems or not completely seal. For example, PML valve covers have a rail to hold the gasket in place while placing the valve cover and gasket on the cylinder head and if a thick gasket is not used, the rail may contact the cylinder head, preventing a good seal.
PML Valve Covers Compared to Stock
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These images show a PML valve cover compared to the stock cover. The outside dimensions are shown. The distance to the gasket surface maybe different
