A
little info about NASCAR Cylinder Heads you should know. First of all, all
Winston Cup and Busch cylinder heads are cast of aluminum alloy and they’re a
great bargain if they suit your application. Just about every engine builder
uses the very best performance components available. For example, the porting
job is usually CNC machined from a computer engineering design that costs
millions. Del West Titanium valves and retainers are used almost exclusively.
Isky “Tool Room” or equal valve springs are used. Most Intake and some Exhaust
valve seats are of an exotic metal called Beryllium (an aerospace alloy), for
greatest heat transfer and durability. About the only valve train assembly
(rocker systems) used are Jesel or TD and are of the shaft mounted design. Most
all engine builders use specially fabricated valve covers with spray oilers for
the valve springs. These heads cost a typical Winston Cup or Busch Team over
$14,000 to build but that’s where the big HorsePower numbers come from.
A few
caution comments when buying NASCAR Heads. There’s a lot to know about the
value (or lack of value) of a particular head. A lot of heads are discards that
didn’t work out while others are specific design for a specific purpose (such
are restrictor plate engines). These may not be a real bargain especially if
you can’t get THE matching intake manifold. In many cases, the intake manifold
is of equal importance to the heads when it comes to performance. Only a
competent engine builder that knows the head and intake design can match the
two components and get maximum performance. There’s more to know than just
“flow numbers” (what the heads flow in cfm). Combustion chamber size, intake
runner size, intake runner location and angle, valve location and more are all
things important when you spending thousands of dollars.
Chevrolet
Heads
Chevrolet Heads as used by NASCAR come in three (3) basic
configurations, 23 Degree, 18 Degree and SB2.2. All three are aluminum. There
are some aftermarket heads (such as Brodix and AirFlowResearch) that are
different and are not used by NASCAR Teams because they are not allowed by
NASCAR Rules.
Pricing for these heads depends on many factors and should
be discussed with one of our Technical Staff members.
23
Degree
This aluminum head (commonly called Pontiac) for small-block
V8s offer a substantial increase in both airflow and horsepower with minimal
preparation. It has a standard intake port location, and is compatible with
most small-block V8 components Note that the intake runners on each side of the
engine are connected (Siamese) in pairs Ductile iron valve seats were used but
some have upgrades. Standard length 2.100" intake valves and 1.625"
exhausts are common. Phosphorous bronze guides are usually installed in this
head. 62cc combustion chambers are original but other sizes are common
depending on purpose. These heads use 3/4" reach gasketed 14mm spark
plugs.
18 Degree
These aluminum 18º cylinder heads were released for
Chevrolet 350, 9.1 compression NASCAR racing engines. . Note that the intake
runners on each side of the engine are connected (Siamese) in pairs. These
heads are similar to P/N 10134364, except they have an additional .080" on
the deck and an added .055" to the intake manifold flange to maintain port
alignment. To raise the compression to meet your need, you can machine the deck
surface. Valve spacing is 1.935". This head is recommended for cylinder
bore diameter of 4.000"-4.155". Intake valve seat material is almost
always beryllium copper. Exhaust valve seat material is usually beryllium
copper. Valve guide material is manganese bronze. Valve guide clearance
("Typical" valve stem diameters): intake is 0.0012" and exhaust
is 0.0016". 65cc combustion
chambers are original but other sizes are common depending on purpose. Fully
CNC ported. Required Components: Common Intake valve diameter is 2.15";
"back" angle is 12 degrees; length is 5.45" or 5.55".
Exhaust valve diameter is 1.625"; "back" angle is 25 degrees;
length is 5.45" or 5.55". Rocker arms (shaft mount): intake (with
flat tappet) is 0.550" offset; intake (with offset roller lifter) is
0.450" offset; exhaust is 0.150" offset. Recommended Accessories:
Intake manifold is P/N 10185053, 24502481, 24502487, or 24502579; intake
manifold gasket set is P/N 10185007; head gasket is P/N 10185054; rocker cover
P/N 10185064.
X-Ray 18 Deg. Head: This 18º V8 head is the same as P/N
24502580 except it is x-ray inspected to insure quality, then hot isostactic
pressed (hipped) to remove porosity, and it then receives special low volume
heat treatment. This head was designed for 9.1 NASCAR engines.
SB2
& SB2.2
Caution is recommended if buying there heads in that many
parts are not available (or are very expensive) for these heads. They are
physically different than the SB2.2.
Released in 1996, these SB2 (small block second generation) heads are
designed for maximum effort competition, improved durability, simplified
preparation procedures, and reduced overall cost of building and maintaining an
S/B V8 racing engine. The intake valve ports are relocated to orient the intake
runners toward the carburetor. The obvious difference is that the center two
intake runners are separated like a Ford and unlike the 23 Degree and 18 Degree
Siamese ports. The result is a distinctive "mirror port" arrangement
that is a significant advance over conventional siamesed and symmetrical port
designs. The exhaust ports remain in the traditional siamesed center port
design with coolant passages between the ports that eliminate the need for
additional machining and auxiliary water lines. SB2 heads provide "out of
the box" airflow performance that is comparable with highly modified
conventional castings. The revised valve layout improves valvetrain reliability
by improving pushrod angularity and reducing or eliminating rocker arm offset.
It also enhances piston durability by changing the depth and location of the
valve pockets in the piston tops. The intake valve angles are 12º by 4º and the
exhaust valve angles are 8º. The as-cast combustion chamber volume is 28cc; intake
volume is 196cc. Recommended intake valves are 2.15" and exhaust valves
1.625" with valve length of 5.55" and valve seat intake 2.20" x
.312" and exhaust 1.67" x .275". Technical Notes: A Special
block P/N 24502600 (with revised lifter spacing/angles) is required only when
using a flat tappet camshaft. These heads also require the following special
components: upper intake manifold P/N 24502588, lifter valley cover P/N
24502587, spring oiler kit P/N 24502597, head gasket P/N 10185054 and rocker
cover (not available). The following aftermarket items are available: head bolt
kit from ARP P/N 234-4722; camshaft from crane flat tappet with 106º lobe
separation P/N PL950266 and 109º lobe separation P/N PL950276 and roller cams
are also available; rocker arms from Jesel; pistons from JE; special gaskets
are required from Fel-Pro; valley cover P/N 1242; rocker cover P/N 1655; intake
manifold, .030" thick P/N 1237, .045" thick P/N 1237-2, .060"
thick P/N 1237-3, .090" P/N 1237-4, .120" thick P/N 1237-5. Wrench clearance
for the nut on the short outer studs is limited. A 7/16" 12 point box end
torque adapter (Mac Tools P/N XB142 with 3/8 drive) is recommended.
SB2.2
This aluminum cylinder head, designed for Winston Cup
competition style racing, is very similar to the SB2 head P/N 24502559 released
in 1996. This head was designed to improve durability, simplify preparation
procedures, and reduce the overall cost of building and maintaining a small
block racing engine. Intake ports are a "mirror" design; exhaust ports
remain the same as original SB2. All eight ports are angled toward the center
of the engine. The SB2.2 has an 11º by 4º intake valve angle and 8º exhaust.
The intake valves centerlines were moved 0.250" closer to the intake
flange and 0.080" toward the cylinder bore centerline. We recommend a
2.15" intake valve and overall length of 5.65", and the exhaust
valves were moved 0.014" outward. The spark plug holes were moved
0.125" toward the center of the bore for combustion efficiency. This head
is redesigned to use shaft mounted aftermarket rocker arms, and the rocker
cover rail was rolled five degrees toward the intake flange to increase
clearance for the intake rocker arms. The valve spring pads were increased for
use of 1.625" valve springs. Material has been added to the deck surface
for a 48cc combustion chamber, and with a flat top piston it gives 12.1:1
compression. This head has been x-ray inspected to insure quality, then hot
isostactic pressed. Replacement intake port plugs to plug bolt holes in intake
runners are size AN-8 with four per kit, P/N 12480171.
Ford
Motorsport (SVO) Yates heads are designed for a max effort
racing engine. There are currently 3 different style castings for a Yates head:
The C3,C3L and C35 are Conventional YATES cylinder heads with standard castings. These heads are usually low compression when new and come from the factory with 67 cc chambers. They were designed for “all out racing” including Drag, Circle Track and Sprint Car applications. Utilizes shaft mounted rocker system but you have to be sure which one you need (one piece mount or multiple ).Typically came with Titanium 1.60” exhaust and 2.1” Intake valves. They have added water passages between combustion chambers and utilize AGS series spark plugs.
The C3H “High-Port” is similar to the standard C3 casting
but has raised intake runners with a straight in intake bolt pattern (bolt
holes are perpendicular to the head). Fits 302 and 351 SVO Ford blocks and come
new with 40 cc combustion chambers.
They were designed for “all out racing” including Drag, Circle Track and
Sprint Car applications. Typically came with Titanium 1.60” x 5.26” exhaust and
2.1” x 5.45” Intake valves. This head uses the same shaft mount rocker system
as the C3L but longer pushrods. Exhaust ports are the same as the C3L and
utilize AGS series spark plugs.
The SC1 is a "all new" Yates casting with raised
intake and exhaust runners ( ,40” over the C3L heads). Which creates better
airflow and greater horsepower. Fits 302 and 351 SVO Ford Racing Blocks. This head also incorporates extra material
for higher flowing port designs. Intake valves go up to 2.180” x 5.685” and
exhaust go up to 1.625” x 5.565”. Uses M-9424-W352 Intake manifold and AGS
series spark plugs.
Most all are machined for shaft mounted rocker assemblies
(Jesel or T & D) but some use 1 piece stands and some use multiple piece
stands.
18 Degree Intake GM# 10185053
This
aluminum intake manifold is designed exclusively for competition. It uses the
new Chevrolet 18º cylinder head (P/N 10134363). This utilizes a high port
runner and four-barrel single plane design, and has the same benefits as the
Bow Tie Intake manifold P/N 10051103 (above). The overall height of this
manifold is 6.75" with Holley bolt pattern. Sells new Un-Ported for over
$300.00
23
Degree Intake GM# 10185063
This manifold is used on all ZZ series 350 HO engines and also can be used on all small-block Chevrolet's thru 1986. This aluminum manifold produces the same horsepower as the previous high-rise design, but provides increased hood clearance and more versatility. It has a dual-pattern flange that can accommodate both standard-flange Holley and spread-bore Quadrajet four-barrel carburetors. This manifold has provisions for all late-model accessory brackets, EGR (exhaust gas recirculation), and an integral hot air choke. A heat shield can be mounted underneath the manifold to prevent coking when EGR is used. Technical Notes: This manifold carburetor flange is approximately 1/2" lower than the LT1 manifold. Sells new un-ported for over $195.00
SB2.2 Intake GM# 12480048
This aluminum manifold is used with valley cover P/N 12370840 on SB2.2 cylinder heads for NASCAR type racing. This is the new design spider upper manifold similar to P/N 245025988 which is used on the SB2 engine. This upper manifold is designed for NASCAR style racing high RPM engines. This manifold has more material in the runners and plenum to allow more flexibility in porting. Sells new un-ported for over $500.00.
SB2.2
Valley Cover GM #12370840
This
aluminum valley cover is used with manifold runners P/N 12370854 on SB2.2
cylinder heads for NASCAR racing. Sell new for over $250.00.
Performer
RPM (1500-6500 RPM) #7101
Designed for 1955-86 262-400 c.i.d. Chevy V8s for
maximum power and a broad torque curve for high-performance street/marine.
Provides power like a single-plane and throttle response like a dual-plane. Has
provisions to add oil fill tube. No provisions for exhaust heated or
stock-style choke. Accepts late-model waterneck, air-conditioning, alternator
and H.E.I. Will fit cast iron Chevrolet Bowtie heads, but will not fit 1987 and
later cast iron heads. Will not fit under stock Corvette hood.
Torker II (2500-6500 RPM) #5001
Designed for 1955-86 high-performance street 262-400 c.i.d.
small-block Chevys. Manifold accepts late-model waterneck, air-conditioning,
alternator and H.E.I. Will fit Corvette and 1987 and later stock aluminum
heads. Will not fit 1987 and later cast iron heads and will not cover port
openings of Chevrolet Bowtie or LT1 heads. Not for heavy vehicles (trucks, vans
etc.); use Performer #2101.
Performer RPM SBF 302 (1500-6500 RPM)
Designed for street 289-302 c.i.d. Ford V8s. This dual-plane
high rise manifold has excellent high rpm power while retaining throttle response.
#7121 is stock replacement/street legal part for Shelby Mustangs with 289
c.i.d. V8 with OEM 4V carb; 1965-66. No provisions for exhaust heated choke.
Available with standard finish or polished.