> There are very early C3 heads (I think early 90's) with canted valves which
> use Cleveland rockers, and a lot of people call them Yates heads because of
> the C3 casting.
True. The early low port C3 Yates and late high port C302B both carried the
same M-6049-C3 part number. Also Ford used recycled part numbers on some of
the intake manifolds so there are Yates and C302 intakes that carry the same
part number. They are similar but the intake port location is slightly shifted
> Later Ford took out the canting and during the 90s made a series "Yates"
> heads with staggered rocker pads.
The C3 Yates was based upon the C302B. The cant angle was removed from
both the intake and exhaust to allow for a more compact combustion chamber
so very high compression could be achieved with a flat top piston.
> As George mentioned, these were all cast with very small ports and chambers
> and substantial work is required to use them.
Most carried small combustion chambers but Ford Motorsport listed part
numbers (C3L and C35) with 67 cc CNC'd combustion chambers. Yates heads
evolved over the years with different port locations and shapes. The C3H
is a raised intake port version of the C3 (exhaust is the same as the C3).
The SC1 is a different heads with C3H intake ports and raised exhaust
ports (relative to the C3 and C3H). The SC1 was listed in the catalogs
as "High Port Head for All Out Performance" but has nothing in common with
the earlier high port family. There were also C34 and C35 variations of
the basic C3 (either CNC machined or unmachined). The D3 is current NASCAR
head. It is based upon an SC1 but the intake is canted (exhaust valve is
not canted). The D3 has very small but extremely active ports which can flow
well over 400 CFM.
> I have about 2000 casting date restrictor plate heads with pretty small ports
> which still flow about 340 at .600 lift on the intake. I think that would be
> really hard to get with most of the aftermarket heads with ports even close
> (as in small) to Mine. I think this is ideal for a street motor and is
> because of all the development that has gone into Yates heads.
True. The same can also be said for the C3/C302/C302B heads (and BF300's).
My C302B's have very small ports and flow 331 CFM at 0.600" lift with a
very strong exhaust port. The advantage the C302B family has is they are
a more direct replacement for a 351C head and use the same pistons, rockers,
valves, etc. Also a wider selection of intake manifolds is available,
including IR EFI and Weber intakes. Off the shelf Pantera headers are also
More on the High Port Family of heads follows:
Ford Motorsport High Port Family
These were Ford's racing cylinder heads before the Yates cylinder heads
were introduced. The high port canted valve aluminum heads included
three basic designs: the A3, B351, and C302. The A3 was the earliest
of this family of heads. They were basically an aluminum evolution of
the Pro Stock high ported iron 4V's. Back in the '70's, when 351C's
were campaigned in the Pro Stock drag class, it was standard practive
to cut off the exhaust ports of iron 4V Boss 351 heads and bolt on an
aluminum plate that had a raised exhaust port location. Some racers also
filled in the bottom 1/3 or so of the intake port with epoxy or aluminum
port stuffers. The A3 is basically an improved aluminum version of a
Pro Stock high ported 4V head. The intake port is the same width as
an iron 4V (and is in the same location) but the lower portion is filled
in. The exhaust ports are circular in cross section and radically
raised compared to a 4V exhaust port so custom headers are required.
For an intake manifold, you can use a 4V with the ports filled or
a Ford Motorsport A331 (by Edelbrock). Any of the other (non-Yates)
Ford Motorsport high port intakes will also work but will have narrower
ports. The A3's have the largest ports of the lot (241 cc intake and
134 cc exhaust) and were optimized for 355 cid and larger engines used
in drag and circle track racing. The B351's came on the scene next.
They had smaller 223 cc intake and 106 cc exhaust ports and were
optimized for NASCAR 355's. The C302's were the final version of these
heads and had the the smallest ports (212 cc intake and 95 cc exhaust,
optimized for 320 cid and under Trans Am engines). They were also
designed to permit (require) custom porting for larger displacement
applications. Late versions of the C302B's carried a C3 part number.
Since this family of heads was originally based upon iron 4V heads, they
are compatible with Boss 302, Boss 351, and 351 SVO valvetrain components
and pistons. Except for the intake and exhaust manifold differences
that are required by the port location and shape differences, these heads
were designed to be 1-for-1 replacements for Boss 351 cylinder heads.
They use a Cleveland style quench chamber and standard 302 Boss/351
Boss/351C/351 SVO valve train parts (will accept 2.19"/1.71" valves).
They have cast iron seats and guides (titanium valve compatible) and are
set up for studs and guide plates. They are also cast with combustion
face and front and rear coolant outlets to allow use on Windsor, Cleveland,
and SVO blocks. Pipe plugs are provided to seal the threaded openings as
required. The fact that they are basically bolt-ons, unlike the Yates,
makes them very desirable heads, particularly for applications like Panteras
where off-the-shelf headers exist.
The earliest versions of these heads went by a "Phase" designation and
were originally referred to as Phase 1 (A3), Phase 1 3/4 (B351), and Phase
III (C302, D302) heads. I also have a set of A3 heads that are Phase 1 1/2
that have intake ports that are narrower (look more like the B351 ports)
than other A3 heads. The exhaust side appears to be standard A3.
Apparently, these variations are not unusual as there were various versions
of these heads cast for specific applications and race teams. There were
also minor variations of the these heads. For instance, the D302 was an
unmachined version of the C302.
Roush and Edelbrock cast a variety of aluminum single plane race intakes
for the early high port heads. These intakes are no longer in production,
though pop up on the used market from time-to-time. The Edlebrock Victor
AH-II is still in production (9.2" deck with integral thermostat housing).
Kelly Coffield makes independent runner intakes (EFI of Webers) to match
high port heads on either 9.2" or 9.5" deck blocks. The intakes are
available with or without thermostat housings with end rail shapes to
match either Cleveland or Windsor blocks. Headers for Panteras are also
readily available from several Pantera vendors.
The Brodix BF300 series heads are essentially a copy of the C302B high ports.
Specifications and notes follow:
A3/B351/C302/D302 SVO High Port Canted Valve Aluminum Heads
Part CC's Int Exh Int Exh Description
Number Port Port Vlv Vlv
Vol Vol Dia Dia
CC's CC's In In
M-6049-A3 62 241 134 2.15 1.71 optimized for 355 cid
and larger, drag racing,
circle track, etc.
M-6049-B351 62 223 106 2.15 1.65 optimized for NASCAR
M-6049-C302 62 212 95 2.15 1.65 optimized for Trans Am,
320 cid and under
M-6049-C302B 62 212 95 2.15 1.65 designed to permit
custom porting, not
legal for Winston Cup
M-6049-C3 62 212 95 2.15 1.65 designed to permit
custom porting, not
legal for Winston Cup
very similar to C302B
M-6049-D302 62 212 95 2.15 1.65 same as C302 w/o port
throat machining or
M-6049-D302B 62 212 95 2.15 1.65 same as C302B w/o port
throat machining or
not legal for Winston
A3/B351/C302/D302 Head Notes:
1. The M-6049-A3 head has the largest intake port volume (241 cc's)
and exhaust port volume (134 cc's), intake flows 280 cfm @ 25 in Hg
as cast, doesn't respond to rpm transitions as well as B351 or C302,
has slight bend on intake port wall to accomodate pushrods, raised
floor increases port radius, straightening the turn for incoming
mixture and minimizing fuel separation, optimized for 355 and larger,
drag racing, circle track, etc.
2. The M-6049-B351 has intermediate port volumes (223 cc's intake,
106 cc's exhaust, flows 260 cfm @ 25 in Hg as cast, intake port
wall filled around pushrod area to straighten it, intake floor same
as A3, material added to exhaust port floor increasing radius for
flow, optimized for NASCAR.
3. The M-6049-C302 has the smallest port volumes (212 cc's intake,
95 cc's exhaust), at the radius the intake port floor has been
filled about 0.120" which forms a slight hump to lift incoming
mixture and drop it evenly around the valve, like B351 wall filled
around pushrod to ensure straightness, optimized for Trans Am 320
cubes and under, narrow ports for increased velocity.
4. B versions (M-6049-C302B, M-6049-D302B) were revised for durability
but not approved by NASCAR, advertised as "too hot for NASCAR" by
SVO, extra material in rocker pedestal area and at spring seats,
rocker cover raised 0.2", improved heat treat, shoulder added to end
plug for improved sealing, outer bolt boss height raised to provide
common head bolt length.
5. All versions are fully compatible with 302 Boss/351 Boss/351 SVO
valve train parts (will accept 2.19"/1.71" valves) and have cast
iron seats and guides (titanium valve compatible), rocker stud
pedestals are machined flat and holes are tapped for threaded studs
and guide plates.
6. Uses Motorcraft AG-series spark plug (14 mm, 3/4 inch reach) with
7. Head is cast with combustion face and front and rear coolant outlets
to allow use on 351W and 351C blocks. Pipe plugs are provided to
seal openings as needed. On Clevelands, install pipe plug in holes
on end of heads.
8. Originally referred to as Phase 1, 1 1/2, 1 3/4, and III heads.
9. Brodix has recently introduced a bolt-on replacement for the C302B head.
10. Nominal combustion chamber volume for the high port heads is usually
listed at 62 cc's, though Ford Motorsport sometimes lists 65 cc's.
11. Special versions of these heads were made for certain race teams.
I have a set of narrow intake port A3's, for instance.
12. High port heads require one inch longer head bolts or studs. If using
head bolts, also use hardened washers. A3's, B351's, and early versions
of the C302 heads had one short bolt. Later C302B's got common length
13. High port heads were designed to fit both Cleveland and Windsor block
and come with combustion face and front and rear coolant outlets which
get plugged with aluminum pipe plugs as needed. Where the plugs go is
a function of the block, whether or not the intake has a coolant cross-
over, and whether or not you run a remote coolant cross-over. For
instance, if you put high port heads on a Windsor style block with a
coolant cross-over manifold, the plugs go in the ends and the
combustion face and a 0.8" hole is drilled at the coolant cross-over.
The supplied instructions illustrate the options. Use a thread sealer
and make sure the plug is below or level with the deck surface. On
Cleveland blocks, pipe plugs go in the holes on the ends of the heads
(coolant goes from block to head, intake is dry). Also an external
(not in manifold) coolant crossover can be used to take water out the
front of the heads.
High Port Family Gasket Notes:
M-6051-A331: Blue Fel Pro headgaskets for A3/B351/C302 heads on a Windsor
block. Does not have the round water transfer hole required for a
Cleveland block, otherwise same as A341. For 4.0" bore (and likely
overbores up to 4.060"). Solid metallic core with wire encased combustion
seal for competition application. Surfaces are coated with Teflon. Do
not use sealer. Can be used with iron Cleveland heads.
M-6051-A341: Blue Fel Pro headgaskets for A3/B351/C302 heads on a Cleveland
block. Has the one round water transfer hole required for a Cleveland block,
otherwise same as A331. For 4.0" bore (and likely overbores up to 4.060").
Solid metallic core with wire encased combustion seal for competition
application. Surfaces are coated with Teflon. Do not use sealer. Can be
used with iron Cleveland heads.
M-6051-B331: For A3/B351/C302 or iron Cleveland heads on Windsor block.
Same as M-6051-A341 except has bifurcated (enlarged dual) coolant transfer
holes added for improved cooling and upper front coolant hole deleted so
Cleveland or A3/B351/C302 heads can be used on Windsor block.
M-6051-B341: Same as B331 but for blocks bored to up to 4.125" (Fontana,
Dart, or Ford Motorsport race blocks). Bore flange valve pockets have been
added to unshroud intake and exhaust valves. Unique right and left hand
Note: Both B331 and B341 can be used on Cleveland blocks if modified per
Victor Reinz and Cometic also make high port compatible headgaskets.
Fel Pro p/n 1229: A3/B351/C302B heads with 1.83" x 2.20" port opening
Notes: Black material, comes with tube of black RTV, rubber O-ring,
pair of intake manifold gaskets, and instructions, no end seal rails
(make out of cork or use RTV... I prefer cork). Can be peened to size.
The tag on the Fel-Pro part number 1229 gaskets state they are for A3
heads but this is incorrct as the port dimensions are listed (and measured)
as 1.83" x 2.20" which fits the C3/C302/C302B heads. Note that p/n 1229 has
round holes on both ends in case you run coolant through the intake. Also,
1229 comes with a tube of black RTV but no end seals. There is a separate
part number for wide port A3's (1.83" x 2.65") though you can use the 1229
gaskets on larger port openings by placing gaskets against the head and
tapping with a ball-peen hammer around the port opening to get the desired
port size. Note that many C302B's are ported to a larger gasket size, so
the Fel-Pro catalog lists port dimensions. The Ford Motorsport M-9439-A341
gaskets have the correct wide port opening for A3 heads but I think they
are no longer available.
Fel Pro p/n 1417: A3 cylinder heads (1.94" diameter round port size)
Fel Pro p/n 1431: B351/C302 cylinder heads (1.81" diameter round port size)
Fel Pro p/n 1433: Yates cylinder heads (1.86" x 1.68" port size)
Valve cover gaskets:
High ports heads use standard 351C valve cover gaskets. Fel-Pro makes part
number 1636, a thick three layer (cork-metal-cork) valve cover gasket which
improves clearance if you have issues with roller rockers to valve cover