9739-BK | PML Cover Valve Covers For Chevy Big Block, 396, 427, 454, 502, CHEVROLET Script, Tall | Black Powder Coat Finish

Tall height Chevy big block engine valve covers with official CHEVROLET script and fins licensed by GM. Includes mounting bolts and PCV and breather grommets.

Dimensions: 

Check for clearance to firewalls, brake bosters, alternator, air conditioning brackets, and the like.

Number of Bolts: 

7 per cover, on the perimeter

Finishes:

These tall, heavy duty valve covers from PML for big block Chevy engines feature raised CHEVROLET script and fins and top quality construction. The classic CHEVROLET script is licensed from General Motors.

Benefits:

• Traditional design and sand cast aluminum construction for an old-school look and feel
• Taller than standard height and open interior to work with many roller rockers
• PCV and oil fill/breather holes
• Holes have internal baffles cast to reduce oil blow-by
• Thick walls and gasket flanges for strength and a secure seal to the cylinder head
• GM licensed product

Chevrolet big block engines include: 396, 427, 454, and the 502

These valve covers are a bit taller than stock to fit over many roller rockers. Always verify clearance before ordering. Using double gaskets to add height frequently causes leaks. Customers have reported to us that PML tall valve covers eliminated the need for double gaskets and the leaks.

For our standard height Chevy big block valve covers, see PML Part Number 9737.

PML designed these valve covers using original GM cast iron heads. Chevrolet Big block engines include: 396, 427, 454, and the 502.

These valve covers are taller than stock so check for space for larger valve covers.

If using updated Camshaft or roller rockers, some modification may be needed. For example, Mike let us know that his 502 with aftermarket roller rockers and a 283 grind Thumpr from Comp Cams required that he grind a bit on the roller rockers so the valve covers would fit. The roller rockers are a generic kind, gold in color and very squared off. He used a standard gaskets, not extra thick. To get the PML covers to fit, he rounded off the left side corners on two of the roller rockers. The valve covers fit great after grinding a bit off the roller rockers on #1 intake and #6 intake (one intake rocker on each side of engine). He did not remove any material from the valve covers. He was told later by an engine machinist that this procedure is virtually always necessary when you try to put roller rockers on a big block chevy.

Gaskets

Gaskets are not included with these valve covers. PML designed these Chevy Big Block valve covers to work with cork composite gaskets.

Breather and PCV Holes

PML Chevy big block valve covers have PCV and oil fill/breather holes and baffles cast into the covers. The internal baffles help prevent oil blow-by out the PCV and breather holes.

These holes work with standard 1 1/4 inch grommets.

The grommet for the breather is for any a breather cap with a 1 inch outer diameter tube.

Oil Fill

Either the PCV or breather hole can be used for oil fill. A separate oil fill hole and cap is not needed.

To add oil, PML suggests this procedure:

• Remove the PCV valve
• Remove the PCV grommet
• Put the PCV grommet on a funnel
• Cut off the end of the funnel so the bottom of the funnel is at the bottom of the PCV grommet
• Put the PCV grommet back in the valve cover
• Put the funnel the PCV grommet
• Add oil
• Remove funnel and put in PCV valve

Checking Clearance

Engine configurations vary so please check for clearance for larger valve covers. The walls and gasket flange are thicker than stock and the fins and script add height to the top.

Look for clearance on the inside also, especially if you have roller rockers. A simple check can be made if you have the stock valve cover. Set the stock cover on the head and measure the distance, if any, between the gasket flange surface and the head. This cover is approximately 3/8 to 1/2 inch taller than the stock cover. PML tall covers are approximately 3/8 inch taller than our standard height covers.

Some customers have reported that their roller rockers contact the inside of these PML valve covers at corners. PML has heard that grinding a bit off the roller rockers on #1 intake and #6 intake, one intake rocker on each side of engine, can add enough clearance (but this is not something we have tried or endorse).

Inside of Valve Covers

The baffle is cast into the covers. It is the square feature between the bolt holes. These valve covers have an open interior without oil drippers so that there is clearance for many roller rocker systems.