|Stock Aussie 2-V
|351 Australian Cleveland -- 2-V Port
|Stock Aussie 2-V
|351 Australian Cleveland -- 2-V Port
Edelbrock RPM Air-Gap 351-C Manifold
Designed to improve performance on the street or racetrack.
Features an open space that separates the runners from the hot engine oil resulting in a cooler, denser charge.
Offers high-performance street power from 1,500 to 6,500 RPM.
Uses the same technology as found on the Victor Series competition intakes.
Works well with stock 2V cast iron Cleveland heads or the new aluminum heads from Edelbrock.
RPM Air-Gap Manifold for 351 Cleveland Ford V8s...............#7564* $345
See More Edelbrock Manifolds
An update on the dyno testing. We're currently testing the unported iron
4V heads. As a quick re-cap, we previously tested the CHI 3V aluminum
heads along with the Pro Comp copies. Fitted with the Scott Cook dual
plane intake, the CHI 3V heads made right at 400 HP and 400 ft-lbs
of torque (420 HP and 420 ft-lbs when corrected for the dyno absorber)
through the mufflers. We had some trace detonation so backed off the
timing a few degrees which dropped the uncorrected HP to 395 (415 HP
corrected). Switching to the single plane CHI 3V intake manifold picked
up 20 HP (436 HP corrected). The stock ANSA Pantera mufflers cost a
whopping 50 HP compared to the 3" inlet/outlet Magnaflows.
For the second round of testing, we replaced the CHI 3V aluminum cylinder
heads from Australia to the Pro Comp knock-offs from China. We tested
the same intakes (Scott Cook dual plane and CHI 3V 4150 pattern single
plane). On the flow bench the Pro Comps were down considerably to the
CHI heads and this was backed up on the dyno. The best pull with the
Pro Comps was 378 HP and 381 lbs-ft of torque (397 HP and 400 ft-lbs
corrected). What worked on the CHI as far as timing (32 degrees) and
carburetor spacer (4 hole 1 inch) also worked the best on the Pro Comp
For our third round of testing we switched to unported iron 4V closed
chamber heads. Interestingly, the unported iron 4V's made better power
than the Pro Comps. Fitted with a Holley Strip Dominator single plane
and a 1" HVH spacer, the 351C made 397 HP and around 380 ft-lbs (417 HP
and 399 ft-lbs corrected). The Parker Funnelweb was tested next. It
picked up around 10 ft-lbs in the mid-range but was down about 6 HP at
the peak. An Edelbrock Torker was tried next which performed about as
well as the Parker for HP and the Strip Dominator for torque. The Parker
worked best with a 4 hole 1 inch spacer, while the Strip Dominator and
Torker prefered the HVH. The final test for the evening was with the
Torker intake manifold but with the 1 3/4" diamter long tube headers and
Magnaflow mufflers replaced by the OEM 351C-4V cast iron exhaust manifolds
and a short elbow of pipe (no mufflers). The result was 366 horsepower
and 351 ft-lbs of torque (uncorrected), a nearly 30 HP/30 ft-lbs drop!
The engine also sounded rather odd and the increased back pressure upset
the idle quality noticeably. Combine this test with the muffler test,
and it's easy to see you can throw away a bunch of HP on a 351C with a
Dave noted the 3.5" stroke 351C with iron closed chamber 4V heads required
more timing than the 4" stroke 408C strokers he's tested with the same type
Rather than mill and drill the unported iron heads for studs and guide
plates, we used the bolt-down roller rockers from Randy Malik at R.M.
Competition. These are fully adjustable aluminum roller rockers
manufactured by Harland Sharp to Randy's specs whichare dedicated Ford
351C/351M/400/429/460 rocker dimensions. Randy says they will withstand
spring pressures in excess of 475 pounds open and over 625 pounds open
when using the option Jesel bolts. These rockers are not the old style
flat top Harland Sharp rockers and are shaped more like the Crane Gold
We've got a bunch more intakes to test with the unported iron 4V heads
but I thought it was time for a quick update.
Cleveland Heads on Windsor blocks.
To allow for the differences in coolant flow between the 351C heads and the 289/302/351W blocks, makes these simple modifications. Because the 351C has a dry intake manifold, coolant doesn't flow between the head and the manifold, flowing instead through the block-mounted thermostat. With the 289/302/351 Windsor engines, coolant flows from the head into the intake manifold where it flows through the manifold-mounted thermostat. The first 351C head modification is to bore a hole in the head (A) to allow coolant flow into the 289/302/351W intake manifold. Bush Performance closes off the cooling passage between the head and block by making a round hole out of a square hole. Then it plugs the round hole with a freeze plug (B). Additional water jacket holes are drilled in the block as shown for better cooling.
How to put Clevelands heads on a Windsor
Clevelands Midlands 302s
High Performance Options for the 351M/400 Engine
BACK TO CLEVELAND ROCKS
The Yates and SVO high ports are an evolution of 4V Cleveland
heads and bolt right on to Cleveland blocks. The will also bolt to
Windsor (and Fontana, SVO, and Dart race) blocks. They come with plugs you
swap around to match the coolant passages of the block you use. Intakes
are available for 8.2, 9.2, and 9.5 inch deck heights.
> There is really no aftermarket head choices for a Cleveland, I have heard
> alumimun ones are avalible but pricey and not 100% proven.
There have been and are a variety of choices but most have not been a
simple replacement head. Windsor aftermarket heads evolved primarily
along a stock replacement head path while Cleveland-based heads were
designed for pure race applications like NASCAR. Because of this, most
of the aftermarket Cleveland heads have raised ports (like the A3, B351,
C302B, Blue Thunder) and/or revised valve angles (Yates, SC1).
The list of heads that can be bolted to Cleveland blocks for which intake
manifolds exist includes:
Ford Experimental Trans Am aluminum 4V cylinder heads
Ford Motorsport High Port family (A3, B351, C302, etc.)
Ford Motorsport Yates family (C3L, C3, C3H, etc.)
Ford Motorsport SCI
Brodix-Neal BF200 series
Brodix BF300 series
Cylinder Head Innovations 3V
Air Flow Dynamics 2V
Bennet canted valve cylinder head
The closest to bolt on that is currently exists are the Australian
aluminum heads (AFD and CHI). Jon Kaase is using the CHI heads on his
Engine Masters entry. Also, Edelbrock is rumored to be bringing out an
alumunum 351C head, though when is anyone's guess.
> I like my Cleveland motor & understand the roll cylinder heads play in it
> making the power it does. However, I am odds with understanding other heads
> I see, such as Yates, SVO, & Roush. With the standard 4v heads as a basis,
> how do the above heads differ?
I keep a lengthy database on just that subject that's too long to post
here but I'll try to cover some highlights. The Ford Experimental Trans Am
aluminum 4V cylinder heads were essentially aluminum duplicates of the Boss
302/351 cast iron 4V head. The Ford Motorsport aluminum high port family
(A3, B351, C302) evolved from the iron 4V Pro Stock heads. 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. The A3's
were followed by B351's and C302B's. 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 narrower 223 cc intake ports and smaller 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.
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. A variety of intakes were available.
The C3L Yates heads are an evolution of the C302B head and were originally
introduced to contend with restrictor plate rules. The valve angles were
changed (to 7.5 and 8.0 degrees with no side cant) to reduce piston valve
relief depths and permit higher ring packaging. Also, the combustion chamber
shape was revised for very high compression static compression ratios. The
resulting head requires a custom aftermarket rockershaft system, different
pistons, valves, and pushrods. The ports were also made small to allow
custom porting and require extensive porting to produce the desired flow
Also, the small Yates combustion chambers (40 cc's) and are designed to
operate with custom pistons that are dished with a mirror image of the
combustion chamber. You can get Yates heads in a larger combustion
chamber size but the extra power they provide over the earlier
A3/B351/C302 heads is mainly in the chamber/piston design. Some racers
maintain the earlier SVO heads are superior to the Yates (at least the
early versions) in non-restrictor plate applications.
The Ford Motorsport SCI is often refered to as a Yates head but is actually
a separate design. Ford lists it as "High Port Head for All Out Performance"
but don't confuse it with either the pre-Yates high port heads or the C3H
high port Yates heads.
The Blue Thunder 351C head is a hybrid cylinder head with 351C valve
locations, chambers, and valvetrain but Yates ports, aimed at the budget
racer. Two things that drive the out-the-door cost on Yates heads are
that they require extensive porting and an expensive rockershaft system.
To keep costs down, the Blue Thunder heads come essentially pre-ported and
retain compatibility with Boss 351 valve train bits. Standard 351C guide
plates, rocker arms, studs, and stud girdles can be used, though a rocker-
shaft system is also available. Longer than stock valves are required and
the seats will accept diameters from 2.02" to 2.2" intake and 1.6" to 1.7"
exhaust. Since valve locations are the same as 351C's, 351C pistons can be
used. 5Occ and 70cc combustion chambers are available. The heads have a
0.400" thick port walls and are partly machined for alcohol down nozzles
that can be finished with a hand held drill.
As near as I can tell, the intake ports are based upon a ported version
of a Ford Motorsport SCI head. A friend compared a set with his Chapman
ported SCI's and said they look very similar. One the exhaust side, the
buyer has a choice of ports. The standard exhaust port is a raised one
similar to a ported C3H or SCI. The optional exhaust port has a double
Cleveland bolt pattern. The lower pattern is stock Cleveland height with
a port that functions as a "stuffed Cleveland" port, in which the bottom
of the port is filled. The second pattern is .750" higher and aligns the
floor of the port with floor of the flange. The top of the port can then
be cut out to match the flange for increased exhaust flow. The only
intake manifolds that are compatible are the 9.2" deck height C3H/SCI
compatible intakes from FRPP and Edelbrock. Blue Thunder may make an
adapter plate for 9.5" applications.
When Ford dropped the C302 high ports in favor of the Yates heads, a
void was formed in the market that Brodix filled with the BF300 series
heads which is a revision to the C302 heads. The BF200 series are a
competitor to the raised port Yates heads.
Then there are the Aussie aluminum 351C heads but this message is long
> I understand that these are all hi-performance pieces, but a standard 4v
> heads also has tremendous potential.
The trend in Motorsport race heads was smaller ports to allow more extensive
porting, smaller valve sizes, raised ports but increased flow. All good
things when it comes to race heads plus they weigh about half what the
heavy iron Cleveland heads weigh.