
See our other listings for the AFR Enforcer heads for use with hyd. flat tappet cams, solid roller cams, with angle or straight plug design, and non steam hole applications. Be sure when selecting the heads you need for your application. We are offering these heads in a much broader selection than any of the other sellers.
Important note.
These heads will include a full set of genuine ARP rocker studs, we will allow you to chose the stud size, 3/8’s or 7/16’s. So be sure to let us know what stud size you would like.
Important note.
Our eBay user id is: skipwhite, and our eBay store name is whiteperformance1. You may have noticed other sellers using a similar name offering similar products. These other sellers have capitalized on our name as we see it, and many customers searching for us will inadvertently find them, thinking we are one in the same company. There is only one “Skip White.” We are the original premier eBay seller under this name since approximately 2003. We have no other eBay names, nor are we associated with any other company regardless of the similarity in the name or location. Our official company name is Skip White Performance. Please see the article in the lower part of this ad for a more detailed explanation.
AFR Enforcer 65cc 200cc ALUMINUM HEADS
The AFR Logo’s clearly display the true mark of excellence that these heads are known for.
In the flowchart below, the AFR Enforcer heads are superior to the Procomp/Speedmaster heads in flow rates, and also edge out the Dart SHP heads on the intake side. The intake numbers are far more important than the exhaust. The overall average flow numbers on the AFR heads are higher than most any brand of non cnc’d cast aluminum heads on the market of an equal runner size.
Notice the intake ports on the AFR Enforcer heads. They allow for a perfect fit with most intakes on the market. Our engines all include an intake manifold. The picture below is one of our engines in the build process.
The difference in horsepower and torque generated by the AFR Enforcer heads is monumental compared to any of the low cost sbc heads on the market.
Assembled by AFR with premium metric competition grade valves, Pacaloy dual springs, Viton valve seals
THE BEST FLOWING, BEST QUALITY SBC ALUMINUM HEADS ON THE MARKET FOR THE MONEY.
This sale is for one fully assembled set of heads (2 heads).
The springs in these heads are set up to operate with hydraulic roller cams up to .600 lift. For those running hyd. flat tappet cams, see our other listings for these heads with the part number AFR Enforcer heads with the part number 272 in the title.
The AFR Enforcer aluminum heads have 65cc combustion chambers with 200cc runners, 8mm metric 2.02/1.60 stainless valves.
PART NUMBER # STR.P-274-AFR
The AFR Enforcer cylinder heads are made from AC4B alloy and tempered to T6 standards. Details about this alloy are in the lower section of this ad.
We certainly know where to draw the line with low end products, and we continue to eliminate parts that we once accepted but that eventually had problems. Sometimes it’s not that a particular product has had a problem that leads to its elimination; something better just comes along. The AFR Enforcer cylinder heads are that “something better” coming along. We now use the AFR Enforcer heads on all of our 350, 383, and 406 engines. The performance has been outstanding on every combination we have tried them on.
The Felpro 1206 is the intake gasket part number is the most common used with these heads Some intake manifolds will set too low due to their design, and the 1266 extra thick intake gaskets may be required. You may also be able to use the Felpro 1205 intake gasket depending on the style of intake used.
Very Important Note.
If you are using an Edelbrock Performer EPS intake then you will need to use a 1205 intake gasket instead of the 1206. This is due to intake flange not covering the top of the 1206 intake gasket properly. The 1205 is slightly small for the AFR Enforcer heads, and may need a very slight amount of trimming to avoid any gasket materiel hanging over into the intake runner. We have been through this procedure in our engine room many times for engines using the Performer EPS intake.
These heads are also available in angle plug style, and for use on engines that do not require steam holes. See our other listings.
A breakdown of the part number.
272 designates
the use of standard length valves, and single springs with a damper setup for hyd.
flat tappet cams. The
274 designates the use of longer valves with dual springs with a damper,
setup for hyd. roller cams. We also have the valve train setup for solid roller
cams, and will have the number 919 rather than 272 or 274. The heads listed
with the letter “A” in the part number are angle plug design. We also offer these heads without steam holes for GM 350/383 builds. Be absolutely certain of what you need before
buying. Feel free to call us if you need assistance deciding what you need for
your build.
See our other listings for our former line of heads heads with our Competition Series PBM valves that are used to create the 68cc combustion chamber.
After receiving many recommendations from our engine builders,
we came up with the best quality, best flowing heads on the market relative to
cost. The only way you’re going to get a set of heads that flow as well or
better will be to spend at least double the cost or more. We have installed
these heads on all of our 383 and most of our 406 engines for the past 2.5 years. Many of these engines were dynoed on our Superflo dyno. The engines
had every possible combination of cam, intake and carb. The results have been
amazing. These heads are excellent in design and quality. Our choice of
hardware and precision assembly also contribute to the performance and
reliability of the heads.
These heads can be used with outer perimeter or center bolt valve covers.
Recommended accessories for these heads.
Please see our other listings.
Part
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Part Number
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Intake gaskets
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· Felpro# 1206 fits perfectly with most intakes. Should your intake drop too low, then the 1266 gasket will correct this problem. Our line of intakes have worked very well with the Felpro 1206 intake gaskets.
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Head gaskets
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· Felpro 17031-2pc. set. or Felpro 1014-2pc set. These head gaskets are for steam hole applications.
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Exhaust gaskets
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· 5206 oval port. This can vary depending on header style.
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Valve cover gaskets
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· 7483 extra thick
· 7484- regular thickness
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Head bolts
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ARP-134-3601 Strongly recommended.
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Head studs
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· PCE-279-1001
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Spark plugs. See important note.
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· Autolite 3923, head range 3
· NGK 4554, heat range 8
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Pushrods (length needed may vary; check with pushrod checker)
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· HB-BULK-7.250-16 recommended for 274, but this may very depending on many other factors.
· HB-BULK-7.900-16 recommended for 272 hyd. flat tappet applications. This may vary depending on many factors. We offer all sizes of premium USA pushrods.
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Important Note
In the flowchart above, the AFR-200s are superior to the Procomp heads in flow numbers, and also edge out the Dart SHP heads on the intake side. The intake numbers are far more important than the exhaust. The overall average flow numbers on the AFR/NKB-200 heads are higher than most any brand of non cnc’d cast aluminum heads on the market. We guarantee the flow numbers to be accurate, as well as the horsepower numbers produced by them.
Most importantly, all three of these heads were tested by the same person, on the same machine, (Superflo bench 1020) using the same testing method, on the same day. These numbers show the true difference between each brand, and that’s what counts.
The difference in horsepower and torque generated by these new heads is monumental compared to the 210cc Procomp heads. We offer several different cam choices with our 383, 406 and 421 engines, and every combination has shown an increase of up to 50 horsepower and no less than 40 hp over the Procomp 210cc heads. We assumed the new heads would generate a considerable increase in power, but to our surprise, they generated more power than expected.
Many of the dyno passes were run to 6500 rpm as the large cam needed 6300-6400 rpm to make peak power, and you must run past this to determine the fall off point. The super sized cam (choice 1) was run on the heads towards the end. Considering the size of this cam, it was very impressive to see zero issues with the heads or hardware. We made a good 25 passes with the big cam trying out different carb sizes, jetting, intake manifolds, timing setting, and adding the Super Sucker plate last.

ONE YEAR WARRANTY, UNLIMITED MILEAGE.
Here is a rundown on the hardware used in these heads and the assembly process.
Brandname: Air Flow Research
Part Number: 1006×2-Pair
Description:
AFR’s 200cc SBC Enforcer Cylinder heads feature our Permanent Mold “As-Cast” Technology surfaces on the intake runners, exhaust runners and combustion chambers that allows for extremely accurate and repeatable port location/performance. These heads are perfect for your 350 to 421 Cubic Inch operating below 6500 RPM.
They come fully assembled with the identical components found in our higher end CNC ported cylinder heads; such as ARP rockers studs, PAC Racing springs, viton valve seals, AFR adjustable guide plates, machined bead valve locks (not stamped), hardened spring cups our one piece 8mm 21 4N Stainless Steel valves. They are available in straight or angle plug and bare without any parts for the DIY. Sold as a single piece, 2 are required per engine.
Specification:
- Material: A356 Aluminum, see more details on alloy below.
- Intake Port Volume: 200cc true actual runner size.
- Intake Port Dimension: 2.080″ H x 1.270″ x 5/16 Radius
- Intake Port Location: Stock
- Exhaust Port Volume: 76cc
- Exhaust Port Dimension: 1.380″ H x 1.420″ W
- Exhaust Port Location: Stock
- Combustion Chamber Size: 64cc
- Valve Cover Bolt Pattern: Perimeter Bolt
- Valve Angle: 23°
- Valve Spring Pocket Diameter: 1.580″ O.D
- Max Valve Spring Pocket Machining: 1.600″ O.D
- Deck Thickness: .450″
- Minimum Bore Diameter: 4.000″
- Flat Mill: .006″ per cc 56cc Maximum
- Spark Plug Dimensions: 14mm x .750″ w/Gasket Seat
ALLOY INFORMATION.
Our cylinder heads are made from AC4B alloy and tempered to T6 standards. You may have heard the alloys 355 and 356 being used on many heads. The alloy used on our heads is similar but slightly different. The AC4B alloy is commonly used by automakers in Europe and Japan. Take notice of the Rm value. This value indicates the tensile strength of an alloy. As you can see, it’s higher than all the other common alloys in this chart. It’s no surprise as to why we have never experienced a failure of any kind with these heads. Zero failures in the casting, zero failures in the seats and guides.
List of Standard Alloy Characteristics
Alloy +B4: H16
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AC4B
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AC4C
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AC4CH
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AC4D
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AC7A
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Mechanical properties
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Rm (MPa)
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345
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285
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260
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320
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245
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R0.2 (MPa)
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250
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225
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157
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240
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105
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A (%)
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1.6
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7.3
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16.8
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4.1
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5.3
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Temper
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T6
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T6
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T6
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T6
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F
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Features
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High strength, small elongation Castability: good, for general purposes
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Castability: good Pressure resistance, corrosion resistance: good
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Castability: good Mechanical properties: good
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Castability: good Pressure resistance: good
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Corrosion resistance: excellent, anode oxidized Castability: not good
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Examples of applied parts
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Crank cases, cylinder heads, and manifolds
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Hydraulic parts, transmission cases, aircraft parts, lighting components, etc.
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Wheels, engine parts, hydraulic parts, aircraft parts, etc.
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Cylinder heads, crank cases, fuel pump bodies, etc.
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Parts for overhead contact lines, parts for ships, business machines, and lighting components for aircraft
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The results produced by these heads will vary greatly depending on the type of setup you are running. The engine combos we have dynoed are what most people use for cam and intake selection, and the results are listed below. The engines dynoed were many 383’s, and several 406 and a few 421 cid engines in the 10:1 to 11.2:1 compression range. All ran on pump gas. This will give you an idea about the capabilities of these heads with combinations of cam, intake, rockers, and carb. This may also help you select the proper cam for your build.
As mentioned, below is just an excerpt from several of our engine adds using the AFR Enforcer heads. We also built and dynoed a 350 engine recently with the new AFR/NKB-200 heads for a customer, and will have the actual dyno results in this ad soon. The cams mentioned below are all hyd. roller cams. If you’re using a lower lift than those listed below, then it would be fair to say the hp will drop, but not by much, providing your lift and duration are somewhat close to any of the cams mentioned below. This will give you an idea of what kind of power to expect with these heads, and it can certainly help you choose a cam and intake. These dyno reports show the heads to be the NKB heads. They are the exact same castings as the AFR Enforcer heads. The main difference between the two brands is the hardware used in AFR brand. This hardware used is of exceptional quality. The valves are 8mm metric size, and the valve springs are the Pacaloy high end series, same as used in their top of the line AFR Eliminator heads. The flow numbers picked up just a bit also over our NKB heads, and these high end valve train components also had a 810 gram weight reduction off the valve train. This has many benefits such as the reduction of valve float coming in sooner, and has a great effect on the ability of the lifters to stay operational at higher rpm.
Please do understand that a cam is not included with the heads. This is just a guide to show what you may expect with a given combination when building an engine using the NKB heads.
PART # 180345-10 This is a hyd. roller cam for use with OE roller blocks.
PART # 110345-10 This is a retro hyd. roller cam for use with non roller blocks.
Valve lift with 1.5 Rockers: Intake .565/Exhaust .580
Duration @.050″: Intake .245/Exhaust .253 Lobe sep. angle: 110º Recommended springs #: 274, See our other listings.
Below are our dyno results on one of our engines with a set of our AFR/NKB heads using this cam and a single plane intake. The horse power numbers will usually improve anywhere from 5-10 more than what the dyno results show after the rings have fully seated.
Official Dyno report on our 406 engine with this cam, flat top pistons, and a single plane intake.
Official Dyno report on our 383 engine with this cam and a single plane intake.
Cam choice # 1 and a single plane intake.
PART # 180265-10 This is a hyd. roller cam for use in OE roller blocks.
PART # 110265-10 This is a retro hyd. roller cam for use in non-roller blocks.
Valve lift with 1.5 Rockers: Intake .530/Exhaust .545
Duration @.050″: Intake .233/Exhaust .241 Lobe sep. angle: 110º Recommended springs #: 274, See our other listings.
Official Dyno report on our 406 and 383 engines with the cam mentioned above. The 406 engine had a dual plane intake, yet still achieved over 500 hp with the NKB heads.
Cam choice #2 and a dual plane intake.
This cam and a single plane intake.
PART # 180245-10 This is a roller cam for use in OE roller blocks.
PART # 110245-10 This is a retro style roller cam for use in non-roller blocks.
Valve lift with 1.5 Rockers: Intake .500/Exhaust .510
Duration @.050″: Intake .225/Exhaust .231 Lobe sep. angle: 110º
Official Dyno report on our 383 engine with our AFR/NKB heads and a single plane intake. Considering the low lift and duration of this cam, the hp numbers are excellent.
This cam and a single plane intake.
Check out the results on the dyno reports below using the AFR/NKB heads with one of our new Comp custom ground street rod cams. All of our engines now use the Comp custom ground cams. This cam has a somewhat low lift and duration, and produced amazing hp and torque numbers when using the AFR/NKB heads.
SBC Comp Cam OE HYD. ROLLER 520/540 Lift 236/242 Duration
110 Lobe Sep.
This cam has a step nose for use in oe roller blocks.
Reduced base circle cam. (1.050)
SBC Comp Cam OE HYD. ROLLER 520/540 Lift 236/242 Duration
110 Lobe Sep.
This cam has a step nose for use in oe roller blocks.
Reduced base circle cam. (1.050)
See dyno results below.
Special Grind # 33161
PART NUMBER: 08-000-8-11323
520/540 lift
236/242 duration
110 lobe sep.
Listed below is our 2.0 383 pump gas engine making 508 horse power at 5900 rpm. You would be hard pressed to find a cam of this lift and duration to produce these hp and torque numbers in a 383. We find this size cam to be the perfect all around size to give good drivability yet make outstanding performance numbers. Very little strain on the valve train components with a cam of this size. This engine had our AFR/NKB heads on it, and the regular Speedmaster single plane intake.
The 421 listed below made 526 horse power with this cam and had a set of our low cost 200cc AFR/
NKB heads on it with the 1.5 rockers. Very impressive considering the low cost heads, and size of this cam. Notice the torque numbers in produced. A fairly flat line from 4100 up to 5500 rpm.
Listed below are a few important solutions to preventing valve train issues while having maximum performance and longevity in your engine when running medium to large lift cams.
The solution to running a hyd. roller cam of decent size in an engine and avoiding valve float is an easy fix, thanks to the Howards Max Effort lifters and our Comp lightweight springs. The cost is only slightly more than the regular Howards street tie bar lifters, and they are undoubtedly the most stable hyd. roller lifters on the market without going to all out racing hydraulic roller lifters. The Max Efforts are also very quiet. Not sure what rpm range they can remain stable at, but we have pushed many of our sbc engines up to the 6,650 rpm range in order to establish the fall off point of a particular build.
We now use these lifters with many of our cam choices. We have tried the Morel tie bar hyd. roller lifters on cams in the 550 and higher lift range in the past and found them highly unstable at around 5800 rpm. Well before audible valve float was evident, the horse power numbers were falling sharply due to valve float. Any cam that’s approaching the 550 lift or higher range should not use the Morel street/strip lifters. The Max Efforts were very stable well into the 6500 rpm range and higher. The cam in this ad is below the 550 lift range but close enough to the limit that we recommend the Max Effort lifters.
Head bolt washer recommendation.
The AFR/NKB-200 heads require the use of special head bolt washers, and extended reach head bolts. Using stock length head bolts will not allow the use of the special washers required, as the OE bolts have a limited amount of thread on them. Not using the special head bolts and washers may cause serious damage to the cylinder heads.
Pushrod recommendation.
We recommend not using stock GM pushrods with these heads. The spring pressures on aftermarket heads are somewhat higher than on OE heads. Combine this with the larger lift and duration cams often used, and stock pushrods may flex or permanently bend. The stock pushrods are usually made from a mild 1810 steel that has been heat treated. Under high rpm they will usually flex and cause a loss of lift resulting in a power loss. The engine will usually run erratically when pushrods are flexing. The Spintron valve train dyno proves that inadequate pushrods will flex to a great degree as engine rpm increases.
Some GM pushrods have a welded ball on them, and they stand a greater chance of breaking off with the use of larger than stock cams, and increased spring pressure. We offer pushrods made from 4310 chromoly with an .080 wall thickness. They are superior to any stock pushrod. Our prices on them are the best you will find.
The size that you will most likely need with the AFR/NKB heads will be 7.250. This size has worked well for us when using the Comp high energy or Scorpion brand rockers. There are many low cost pushrods on the market in the $29-$39 range. These low cost pushrods are totally unsuitable for use with these heads for the many reasons mentioned above, and they are not guide plate compatible. They usually have a wall thickness of only .065. These pushrods will cause problems when used on a high performance setup. There are many factors that can determine pushrod length requirements. The 7.250 length is the most applicable. Should you purchase a set of pushrods from us and find that the length is not suitable, you may return them, and we will send out the size you request. It is strongly recommended that you use a pushrod checking device to determine the exact size pushrod needed.
Stud Girdle recommendation.
If you are running full roller rockers, we recommend tall valve covers, and this can cause the oil that is pumped up into the top of the heads to not be deflected back down onto the valve springs, valve tips and roller rockers. The lack of oil on these parts can lead to not only a lack of lubrication but also to a lack of cooling on these parts. Heat transfers up the valve stem from the combustion chamber. This heat is very high in temp, and may cause serious damage to the valve guides, springs and roller rockers.
The cure for this would be to install a low cost set of stud girdles. Stud girdles increase stability to the rockers’ studs, eliminating flex that is may be present to some degree when running cams several sizes over stock, not to mention increased spring pressures over stock. Stud flex robs your engine of power and smooth operation in the upper rpm ranges. As mentioned above, another very important aspect of using stud girdles is that they deflect oil directly back onto the valve springs, valve tips and roller rockers. On a stock engine this is not an issue due to the fact that stock valve covers are very close to the top of the rocker arms.
AFR-200 64CC 200CC RUNNER SIZE STRAIGHT PLUG FOR SBC CHEVY ENGINES
Intake Valve Dia: 2.02″
Intake Port volume: 200cc
Intake Port Dim: 2.2″ x 1.2″
Int Port Location: Stock
Intake Gasket: Felpro# 1206 fits perfectly with most intakes. Should your intake drop too low, then the 1266 gasket will correct this problem. Our line of intakes have worked very well with the Felpro 1206 intake gaskets.
Head Gasket: Felpro# 17031 for steam hole applications
Exh Valve Dia.: 1.600″
Exh Port volume: 70cc
Exhaust Port Dim: 1.356″ x 1.420″ w
Exh Port Location: Stock location & bolt pattern
Exhaust Gasket: Depends on what type exhaust you’re using. Best to try and match up the gasket to your header or manifold
Flow, Intake: See chart above.
Flow, Exhaust: See chart above.
Head Bolts: We strongly recommend ARP # 134-3601 head bolts. Must use extended reach with head bolt washers or head studs.
Head Studs: PC-2451-Studs (12pt) or ARP brand.
Manifold: Most any. Our line of intakes fit very well on the AFR/NKB heads.
Milling: Min. Down to 58.5cc or 64.5 = .060″ See info in this listing for details on this.
Pistons: Most 23°aftermarket pistons.
Push Rod length: When running a hyd. roller cam use 7.250 length, or 7.3 if using our Comp reduced base cams. See our other listings for the best deal on premium pushrods.
Push rod Guide Plate: These heads include a full set of AFR adjustable guide plates.
Retainers/Locks: Chromoly Steel Retainers, with 7° AFR brand machined locks are used on all of our heads.
Spark Plug: Straight, .750″ reach, gasket, Autolite 3923 or NGK 4554 for one step lower heat range than the Autolite.
Spring Pockets: 1.550″ OD (.030″ deeper max)
Springs: Pacaloy premium 1.290″ Dual springs with an internal damper.
Valve Length: 5.015″ (+.100″) for hyd. flat tappet cams or + .200 for hyd. roller cams
Valve Stem Dia: 8mm Metric
Valve Train: STD SBC 3/8″ or 7/16″ stud mount
Valve Guides: 1/2″ OD Int = Mag-bronze Exh = Phos-bronze (.002″ press)
Valve Guide length: 1.950″
Valve Guide clearance: .0014″ – .002″ (with our .3415 dia. valve stem)
Valve Guide Spacing: 1.890″ moved .030″ from stock
Valve Seats: Hardened Ductile Iron, .006″ press
Valve Seat dim. Standard
Valve Seat angles: Int = 32° – 45° – 60° – 70° Exh = 37° – 45° – radius
Stud Girdle: Most all stud girdles will work on these heads with the exception of the AFR Eliminator stud girdles.
Torque: Head Bolts = 65 ft/lb
Rocker Studs = 50-55 ft/lb
Manifold = 30 ft/lb
Block Use: Any SBC Iron or Aluminum
Weight: 59-61 lbs fully assembled pair.
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