Differences In Big Block Chevy Head Gaskets


The Grumpy Grease Monkey mechanical engineer.
Staff member
differences in big block chevy head gaskets and other related info in the links and sub-links may prove critical if you're going to build a big block chevy engine,
you can in some cases, use a Gen V head on a Mark IV block (Gen IV), as long as you use the head gaskets for the Mark IV.
aftermarket heads from some manufacturers are designed to work on almost all COMMON BBC BLOCKS, some OEM (CHEVY HEADS ) WON'T

You cannot use Mark IV heads on a Gen V Block however. You will get water in the lifter valley.

Gen V, and Gen VI heads are interchangable. The Gen V heads have the non-adjustable valve lash.


















Secure sealing between the cylinder heads and the block is a critical component of making reliable horsepower, so Chevrolet Performance puts the same engineering excellence and manufacturing precision into their gaskets, head bolts, and cylinder head studs as the blocks and heads they secure. Big-Block cylinder head gaskets are available in a variety of materials and thicknesses. Piston-to-head clearances should be considered when selecting gaskets. Use Gen V for 1991-1992 applications. Gasket packages contain one gasket unless otherwise specified.



  • With pre-flattened copper wire ring and permatorque/blue stripe coating for engines with aluminum heads
  • Bore sizes between 4.250" and 4.370"
  • Use with Mark IV (1965-1990) engines only
  • Compressed thickness is 0.039"

  • For 1991 and newer Gen-V and Gen-VI Big-Blocks with aluminum heads and 4.250" to 4.370" bore size
  • Has pre-flattened wire ring and stainless core that makes it ideal for saltwater marine use
  • Compressed thickness is 0.039"

  • Head gasket for 1991–2000 Gen-V 454 Big-Blocks



  • For all Gen-V and Gen-VI 502 Big-Blocks with cast-iron heads
  • Has additional water hole for improved cooling of siamesed cylinder walls
  • Includes 2 gaskets (right and left) per package
  • Compressed thickness is 0.041"

  • For Gen-V and Gen-VI Big-Blocks with aluminum heads and 4.375" to 4.540" bore size
  • Has pre-flattened wire ring and stainless core that makes it ideal for saltwater marine use
  • Compressed thickness is 0.039"


  • With pre-flattened wire ring for all 572 Big-Blocks with either cast-iron or aluminum heads
  • Compressed thickness is 0.030"

  • Universal kit for cast-iron and aluminum Big-Block heads
  • Includes (8) 7/16-14 x 2.08" bolts P/N 88960334, (24) 7/16-14 x 4.060" bolts P/N 88960333, (8) 7/16-14 x 5.06" bolts P/N 88960332, and (40) hardened washers P/N 14011040
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The Grumpy Grease Monkey mechanical engineer.
Staff member









Ansen 120-1003 Big Block Chevy Valve Cover Spacers

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Valve Spring Cooling via Engine Oil

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several options exist, in valve cover spacers, and taller valve covers ,obviously. clearance, quality features, and price varies

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valve cover gaskets

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oil system mods that help

heres a short list REMEMBER the object or goal in building and maintaining the lubrication system is too maintain a 100% dependable pressurized cooling flow of lubricant to the bearings, rockers,valves etc. obviously use of a high quality synthetic oil that has a higher heat tolerance and that...

catch can related info

In every engine a small amount of pressurized gases from combustion pressure, during the engines power stroke that's been generated is getting past the rings, as the compression and combustion stroke begins before that cylinder pressure forces the rings out against the cylinder walls. and it...

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Most guys with corvettes stay with the stock valve covers unless forced into swapping , due too clearance issues caused by the need to use roller rockers, stud girdles or other aftermarket valve train accessories. On some corvettes theres serious clearance issues with the windshield wiper motor...

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The Grumpy Grease Monkey mechanical engineer.
Staff member
How to Source Chevy Big-Block Gaskets

many of the recently designed and currently sold aftermarket big block aluminum heads can be used on any of the gen iv-v-vi blocks
this obviously is not true of most factory heads or previously designed aftermarket heads
ictor-Reinz used to make a left and a right (different part numbers!) gasket pair to put Mark IV heads on to a "production" Gen 5 block. Those gaskets are now supplied by Mahle.

4918 is for the passenger-side (right) deck.
4923 is for the driver's-side (left) deck.

https://www.mahle-aftermarket.com/media ... a-g-05.pdf

Bowtie Gen 5 blocks didn't have the coolant-leakage problems because they had more metal in the critical locations for better gasket sealing.

Matching the correct engine gaskets for your particular big-block build is critical for proper fitment and function. This is particularly important when attempting to crossbreed major components between different engine series, such as Mark IV, Gen V, and Gen VI engines. Historical similarities make these versions almost identical in appearance; despite that, they are mutually incompatible.

This Tech Tip is From the Full Book, CHEVY BIG-BLOCK ENGINE PARTS INTERCHANGE: THE ULTIMATE GUIDE TO SOURCING AND SELECTING COMPATIBLE FACTORY PARTS. For a comprehensive guide on this entire subject you can visit this link:

SHARE THIS ARTICLE: Please feel free to share this article on Facebook, in Forums, or with any Clubs you participate in. You can copy and paste this link to share: https://www.chevydiy.com/how-to-source-chevy-big-block-gaskets/

For nearly 25 years the normally well-regarded Mark IV engine series was plagued by oil leakage from the oil pan, the rear main seal, valve covers, and sometimes the timing cover seal. Gen V engines were redesigned in these areas to correct these problems, but the revisions incorporated design changes that made some Mark IV engine components incompatible with Gen V engines. The primary problem is that the engine gasket sets are not interchangeable between these engines. To correct the leakage problems, gasket revisions and sealing issues were addressed in the following areas:

  • Head gaskets
  • Valve cover gaskets
  • Oil pan gasket
  • Rear main seal
  • Timing cover seal
Gen V blocks have revised core holes and coolant passages that make them incompatible with Mark IV cylinder heads. These passages were altered to address coolant leakage problems. Another core hole was required in the front deck surface of Gen V blocks to accommodate revisions to the casting process. Gen V head gaskets block this hole, Mark IV gaskets do not; Mark IV heads and gaskets are not compatible. If you use a Gen V Bowtie block that accepts both Mark IV and Gen V heads the core holes can be tapped and plugged to make the Mark IV heads and gaskets compatible. If not modified correctly water does not circulate properly through the engine and the result is overheating.


This factory head gasket (PN 12363414) is offered for all 1965–1990 big-blocks with bore sizes from 4.250 to 4.379 inches. Compressed thickness is .039 inch and it is for Mark IV engines only. It features a re-flattened copper wire ring and PermaTorque/blue stripe coating for engines with aluminum heads. A .041-inch-thick, 4.374- to 4.540-inch large-bore version is available (PN 12363413).


Chevy offers a snap-in intake manifold oil shield (PN 12555320) to help isolate hot engine oil from the lifter valley and prevent it from transferring heat to the intake manifold.

Gen V and subsequent Gen VI cylinder heads incorporate a machined valvecover gasket sealing rail and matching formed gaskets to eliminate a major leakage source compounded by proximity to hot exhaust manifolds. This makes Mark IV valve covers and gaskets incompatible with all Gen V and VI heads and vice versa. Gen V and VI engines also employ a one-piece rear main seal and a onepiece oil pan gasket. This combination is designed to eliminate the former leakage path at the four corners of the pan where the pan rails encounter the rear main cap and the front timing cover on Mark IV engines that have two-piece rear main seals and a four-piece oil pan gasket.

Timing Covers
Mark IV, Gen V, and Gen VI timing covers are not fully interchangeable. Both Mark IV and Gen V covers are stamped tin with the traditional ten-bolt pattern and two locator dowels above the bottom bolts, but that’s where the similarity ends.

Mark IV timing covers flair outward around the bottom bolts to extend the front gasket to the pan rails. The pan gasket retainer lip on a Mark IV cover is directly on the bottom. On 1990–1995 Gen V timing covers it is offset to the rear with an auxiliary timing tab riveted to a lower extension. Gen VI covers are cast aluminum and use only six bolts. Gen V (1996 and later) engines also use this cover.

If you’re building a Mark IV engine simply use any regular-style GM or aftermarket Mark IV timing cover. Most aftermarket blocks still use the Mark IV–style cover as well. Because the front pan gasket on Gen V covers is offset to the rear, Gen V oil pans are shorter and do not work on other engines.


Many performance builders prefer the convenience of a Fel-Pro Performance R.A.C.E. (remainder to assemble complete engine) set. Big-block sets come complete with the rear main seal, timing cover gasket, thermostat gasket, and gaskets for the water, fuel, and oil pumps.


This close-up view shows anti-crush inserts with a steel core and illustrates the improved sealing surface at each corner of the pan.


To promote improved leak-free sealing Fel-Pro offers this one-piece gasket for all bigblock applications. For newer engines, one-piece molded silicone-rubber gaskets are available. Some have a solid steel core; others have a rigid carrier-type design.

Cylinder Head Gaskets
A bewildering number of choices present themselves when you are contemplating head gasket selection. Builders can choose from a variety of gasket manufacturers including GM/Chevrolet Performance, Fel-Pro, Mr. Gasket, Cometic, Mahle/Victor Reinz, SCE, and others. All of them offer top-quality head gaskets in the proper configuration to suit your application and your block and cylinder head combination.

For performance applications you’ll likely choose a gasket that meets your specific requirements in terms of type, size, shape, sealing quality, etc. Few restorers insist on an original OEM factory head gasket for the engine. Those that do have to seek out a set of NOS (new old stock) gaskets, not an easy task. Most builders go with a contemporary duplicate as long as it meets the same specs. Gasket selection factors also include the shape and diameter of the gasket bore, which is typically larger than the bore size to prevent overhang that promotes pre-ignition and invites mechanical mayhem. Some builders prefer gaskets that closely match the bore after the gasket has been compressed. The idea is to minimize the gap and reduce the combined effect of the three causes of additional volume: the crevice volume between the piston and cylinder wall above the top ring, the chamfer volume at the top of the cylinder, and any additional volume contributed by an oversized gasket bore. Depending on the combustion chamber shape and mixture motion within the chamber, these seemingly inconsequential spaces can trap end gasses that reduce overall mixture quality and promote detonation.


GM brass freeze plugs (PN 88891749) for 1991 and later Gen V and VI engine blocks are smaller in diameter than Mark IV plugs and thus do not interchange. They are suitable for marine applications.

Some Mark IV 427/454 blocks have additional water core passages in the deck surfaces. If necessary, double-check your head gaskets to make sure they accommodate these extra holes. Most gaskets also come with pre-punched holes for applications that use extra head bolt bosses in the lifter valley. If your block doesn’t have these extra bosses the gaskets still work for your application.

Chevy big-blocks accept four different types of head gaskets depending on the performance application or original usage as determined by the factory. They are steel shim, composition, multilayered steel, and dead soft copper (normally with accompanying O-ring).


Gen V and VI head gaskets incorporate different water passage openings at the front and rear. This does not present significant difficulty as long as you select the correct gasket for your application, or a special gasket set designed to accommodate the difference between early- and late-model blocks and heads.


Standard rebuild gaskets, such as this intake set (PN 10174981), for ovalport applications typically include end rail gaskets and a distributor gasket. Most builders discard the end rail gaskets and replace them with beads of silicone sealer. These gaskets have open heat-riser ports.

Steel Shim Gaskets

Embossed steel shim gaskets were used on stock Mark IV engines with cast-iron heads. These gaskets are tough and thin (generally .020 to .022 inch) and they offer a convenient method to increase CR on stock and mildly modified engines. This trick is often used to raise stock 8.5:1 engines to 9.2:1 or so depending on the particular combination of bore size, piston crown, and chamber shape. Shim gaskets reduce your piston-to-head clearance and thus have an effect on piston-to-valve clearance as well. Check this carefully if you are using a high-performance cam. Because pistonto-head clearance is reduced below the normally accepted minimum of .035 inch you must pay careful attention.

Do not use steel shim gaskets with aluminum rods as they easily close the gap once they stretch a bit. They are not RPM-friendly in terms of head clearance. Even with steel rods, you want to maintain the .035-inch minimum specified clearance by adjusting the deck height accordingly. You can’t zero deck the block and then run shim gaskets if you plan to operate the engine at speeds above 6,000 rpm. The pistons will likely kiss the heads unless you build in more clearance with the deck height. Steel shim gaskets should only be used on Mark IV engines; they do not fit Gen V engines. They can work on Bowtie and Gen VI engines, but in most cases you want to use the multi-layered steel (MLS) gaskets specified for those particular engines. When using a steel shim gasket, most builders spray-paint them with a gold, silver, or aluminum head gasket sealer just before installation, but this is really unnecessary. Gasket manufacturers offer no specific recommendations and generally prefer that you don’t paint them.

Composition Gaskets

Composition gaskets are most commonly found in auto parts stores and engine rebuild kits; most of the major performance gasket manufacturers also offer composition gaskets. These gaskets offer good sealing qualities around the coolant passages and they incorporate a formed stainless-steel, or in some cases, copper fire ring around each cylinder opening. Some aftermarket head manufacturers such as Edelbrock offer part-specific gaskets made to fit their own cylinder heads, but in most cases they’re not necessary. From an interchange standpoint your primary concern is to use the correct gasket to accommodate whatever cylinder block and head generation you are trying to mate. By and large, composite gaskets are still the most widely chosen gaskets for street performance use.

Multi-Layered Steel Gaskets These gaskets incorporate three layers of stainless steel sandwiched together to form multiple layers of sealing surface held together by external rivets and the fire rings around each cylinder opening. The outer layers typically have an elastomer coating to promote good sealing around coolant passages. MLS gaskets are capable of withstanding very high CRs without secondary O-rings. They require a deck surface finish of RA-30 or better (roughness average; measured in microns from 30, which is smoother, to 110, which is rougher) on both the cylinder head and the block.


This Gen V gasket is laid on top of a Mark IV gasket with arrows indicating the water passage openings used on Gen V and VI applications. They are not the same as on the Mark IV gasket visible through the holes.


Here’s a Fel-Pro PermaTorque MLS gasket (PN 1077) on a 4.600-inch-bore Dart Big M block. Multi-layered construction requires an ultra-smooth finish on the block deck and cylinder head deck surfaces.

MLS gaskets are now standard fare on many production engines and they have become the preferred gasket for most high-end racing engines. They are made in all configurations so you will have no trouble finding the right gasket to match your particular combination of Mark IV, Gen V, and Gen VI block and cylinder heads. They’re more expensive and most street performance applications can easily get by with the appropriate composite or steel shim gaskets from the same manufacturer.

Dead Soft Copper Gaskets Copper gaskets are used infrequently in big-block applications. They are intended for very-high-horsepower applications and it is unlikely that you’re building anything that needs them unless you’re contemplating a supercharger, turbocharger, or exotic fuel application such as alcohol or nitromethane. Even then, MLS gaskets are replacing copper in many applications.

Copper gaskets often required an O-ringed block or cylinder head and they are notorious for coolant leakage. More recently manufacturers have incorporated elastomer coatings to improve sealing and some incorporate steel O-rings directly in the gasket to eliminate the need for O-ringing the block or heads. One advantage is that they can be custommade to an exact fit for almost any application. The primary manufacturers of copper gaskets include SCE, Milodon, Clark, Copper Head, and Hussey

If you need copper gaskets, you’re likely building a serious piece with an aftermarket block and you probably aren’t too concerned about big-block interchange issues. There is no particular industry standard or horsepower threshold for which copper gaskets must be used. In general, they are typically applied in forced induction– or nitrousequipped engines generating very high cylinder pressure. Copper is a particularly strong material in this application and it remains malleable so it is compatible with the steelO-rings that are typically used to enhance head gasket sealing in these engines.

Chevrolet Performance Head Gaskets
One way to make certain you select the correct gasket for matching dissimilar blocks and cylinder heads is to carefully follow Chevrolet Performance recommendations. Chevrolet has made certain that the correct gaskets for each application are readily available with the correct coolant passages to accommodate any combination of Mark IV, Gen V, Gen VI, and Bowtie big-blocks. Big-block cylinder head gaskets are available in a variety of materials and thicknesses. Piston-tohead clearances should be considered when selecting gaskets. Use Gen V for 1991–1992 applications. Gasket packages contain one gasket unless otherwise specified.

Composition Head Gasket (1965–1990), PN 12363414

  • Mark IV (1965–1990) engines only
  • Pre-flattened copper wire ring and PermaTorque/bluestripe coating for engines with aluminum heads
  • Bore sizes from 4.250 and 4.370 inches
  • 039-inch compressed thickness Composition Head Gasket (1965–1990), PN 12363413
  • Mark IV (1965–1990) engines only
  • Pre-flattened copper wire ring and PermaTorque/bluestripe coating for engines with aluminum heads
  • Bore sizes 4.375 to 4.540 inches
  • 041-inch compressed thickness
Composition Head Gasket (1991-newer), PN 12363412

  • 1991 and later Gen V, Gen VI big-blocks with aluminum heads, and 4.250- to 4.370-inch bore size
  • Pre-flattened wire ring and stainless core; ideal for saltwater marine use
  • .039-inch compressed thickness
Head Gasket, 454-ci Engine, PN 12555728

  • Gen V 1991–2000 454 big-blocks


This factory head gasket (PN 12363414) is offered for all 1965–1990 big-blocks with bore sizes from 4.250 to 4.379 inches. Compressed thickness is .039 inch and it is for Mark IV engines only. It features a re-flattened copper wire ring and PermaTorque/blue stripe coating for engines with aluminum heads. A .041-inch-thick 4.374- to 4.540-inch large-bore version is available (PN 12363413).


This head gasket kit (PN 12366984) for 502-ci engines with cast-iron heads features a compressed thickness of .041 inch. It comes with two gaskets (left and right) per package.


The factory 572-ci big-block gasket (PN 88961561) has a pre-flattened wire ring to accommodate cast-iron or aluminum heads. It compresses to .030 inch and accommodates largebore Gen V and VI blocks.

Head Gasket Kit, 502-ci Engine, PN 12366984

  • Gen V and Gen VI 502 big-blocks with cast-iron heads
  • Additional water hole for improved cooling of siamesed cylinder walls
  • Two gaskets (right and left) per package
  • .041-inch compressed thickness
Composition Head Gasket (1991-newer), PN 12363411

  • Gen V and Gen VI big-blocks with aluminum heads and 4.375- to 4.540-inch bore size
  • Pre-flattened wire ring and stainless core; ideal for saltwater marine use
  • 039-inch compressed thickness Head Gasket, 572-ci Engine, PN 88961561
  • Pre-flattened wire ring for all 572 big-blocks with either cast-iron or aluminum heads
  • 030-inch compressed thickness
Head Gasket, 572-ci Engine, PN 88961561

  • Pre-flattened wire ring for all 572 big-blocks with either cast-iron or aluminum heads
  • 030-inch compressed thickness

Rear Main Seals
Big-blocks use two different types of rear main seal. A two-piece seal used on all Mark IV big-blocks until 1990 and a one-piece seal used on subsequent Gen V, Gen VI, and later blocks. They are not interchangeable. You must use the correct seal for the block and crank combination.


This comparison of a standard Mark IV twopiece rear main seal and a Gen V and VI one-piece seal illustrates their incompatibility with anything but their intended blocks and cranks.


This comparison of Fel-Pro intake gaskets reveals the signifi cant difference between oval-port (top) and rectangular-port (bottom) applications. Peanut-port openings are even smaller than the oval ports. Make sure you are using the correct gasket to ensure a proper seal at the port.

Two-piece seals are familiar to most big-block builders and over time most builders have become accustomed to the newer one-piece rear seals. Two-piece seals are more prone to leakage, but builders who assemble a lot of engines have learned to offset the parting lines from the main cap to block interface and apply a minimum amount of sealer to the edges to remedy the situation. If installed carefully this procedure can prevent rear seal leakage for a long time, but the newer one-piece seals are more foolproof and rarely give problems.

Intake Gaskets
Intake manifolds require the correct gaskets to match the cylinder head ports. There are square ports, oval ports, and peanut ports to contend with so make sure you match the gaskets correctly to accommodate the ports. All intake gasket sets still come with rubber end seals. Most builders discard these and lay a bead of silicone sealer across the front- and rear-sealing surface.


Most standard applications (oval ports) have an opening in the center of the gasket for the exhaust heat passage. Quality gasket sets such as these Fel-Pros come with additional metal manifold restrictor plates to block this passage, if desired.


Standard rebuild gaskets, such as this intake set (PN 10174981), for oval-port applications typically include end rail gaskets and a distributor gasket. Most builders discard the end rail gaskets and replace them with beads of silicone sealer. These gaskets have open heat-riser ports.

The following GM gaskets accommodate 90 percent of all intake gasket requirements and aftermarket sources, such as Fel-Pro and Mr. Gasket, make gasket sets to accommodate special requirements.

Intake Gaskets
Gasket, Aluminum Oval-Port Heads, PN 12366985

  • Designed for big-block aluminum heads PN 12363390, PN 12363392, and PN 12363399
  • Use with manifold PN 12363406, PN 12363407, PN 12363420, or PN 12363421
Gasket, All Square-Port Heads, PN 88962213

  • Use on all big-block engines with rectangular intake port heads 396 through 572 ci
  • Includes two gaskets
Gasket, 454 and 502 Engines, PN 12506106

  • Used on 454 and 502 engines with restricted heat crossover passages
  • One gasket per package; order two per engine


Chevy PN 12366985 fits Chevy oval-port heads, PN 12363390, PN 12363392, and PN 12363399. The heat-riser ports are blocked on these gaskets.


Running a standard-deck intake manifold on a tall-deck block requires two sets of intake gaskets and these manifold spacers from Weiand (PN 8204) for rectangular-port applications. Oval-port versions are also available (PN 8206).

Carburetor Heat-Riser Gaskets
All 1965–1969 oval-port intakes incorporated a heat-riser passage across the front of the carburetor mounting flange. Exhaust heat was routed from adjacent exhaust ports to the carburetor base to provide quicker cold-weather warm-up. This arrangement requires a carb gasket with a slot at the front to match the heat-riser passage in the manifold. A separate metal heat shield mates with the gasket to seal the passage under the carburetor. Without the correct gasket an air leak occurs at the carburetor base. You can block the heat-riser passage from the head at the intake manifold gasket. Special gaskets with metal inserts are available for this and the manufacturers explain it in their catalog listings. In a pinch, many builders cut small metal inserts from soda cans to accomplish the same thing. This generally works well, but requires careful application of high-temperature sealant. The heat-riser crossover passage was eliminated in 1969.

Primary engine fasteners are largely interchangeable. However, main cap bolt lengths differ among Mark IV, later Gen V, and Gen VI four-bolt main engines. Inner and outer main cap bolts for Mark IV, Gen V, and Gen VI blocks are sold individually and Chevrolet offers a universal head bolt kit for cast-iron and aluminum big-block cylinder heads (PN 12367779). Also offered are windage tray studs, hardened washers, and 6- and 12-point nuts individually. The following Chevrolet parts are designed for universal application and may or may not be actually correct in every case. For a more exact fit and broader selection, aftermarket suppliers such as Automotive Racing Products (ARP) make specific bolt and stud kits to suit almost any configuration you require.

O-Ring Seal, PN 6264902

  • Used under the rear main bearing cap on all 1991 and newer Gen V and Gen VI 454 and 502 engines
  • Sold individually
Outer Main Cap Bolt, Mark IV, PN 3859927

  • Used with Mark IV (1965–1990) cast-iron big-blocks with four-bolt mains
  • Sold individually; 10 per engine required
Inner Main Cap Bolt, Gen V and Gen VI, PN 10106461

  • Used with Gen V and Gen VI (1991 and newer) big-blocks with four-bolt mains
  • Sold individually; 10 per engine required
Inner Main Cap Bolt, Mark IV, PN 3909834

  • Used with Mark IV (1965–1990) cast-iron big-blocks with four-bolt mains
  • Sold individually; 10 per engine required
Windage Tray Stud, PN 3902885

  • Used for mounting splash shield (PN 3967854)
Windage Tray Stud, Gen V 454 and 502, PN 10224104

  • Used with Gen V 454 and 502 engines
Windage Tray Bolt, 572, PN 88958656

  • Used with 572 engines Universal Cylinder Head Bolt Kit, PN 12367779
  • (8) 7/16-14 x 2.08-inch bolts (PN 88960334)
  • (24) 7/16-14 x 4.060-inch bolts (PN 88960333)
  • (8) 7/16-14 x 5.06-inch bolts (PN 12367329)
  • (40) Hardened washers (PN 14011040)
  • Use individual part numbers for replacements
  • Use thread sealant on all big-blocks except 502s with blind bolt holes
Hardened Washer, PN 3899696

  • 450-inch I.D. x .860-inch O.D
  • Sold individually
Cylinder Head Stud Nut, PN 3942410

  • Magnafluxed 1038 steel 7/16-20-inch hex-head nut
  • sold individually
Cylinder Head Stud Nut, PN 14044866

  • Magnafluxed 4037 steel 7/16-20-inch 12-point nut
  • Sold individually

Rocker Arm Studs and Guideplates
All Mark IV and Gen VI heads accept standard screw-in rocker studs and guideplates. Gen V–based “net lash” rocker arm stud and ball arrangements are not compatible. Some GM dealers may still carry special rocker stud and nut replacement adapters for Gen V applications (PN 10198929 and PN 10198930). They allow lifts up to .520 inch with stock Gen V and VI rocker arms. You can also select from a broad range of aftermarket rocker studs with a selection of lengths to suit every application in both iron and aluminum heads.



Written by John Baechtel and Posted with Permission of CarTechBooks

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