Ford 351 Cleveland Engine Cylinder Head Sources

There was a time when all you had to choose from for Clevelands were factory iron heads you could spice up with some port work. Today, a large variety of great aluminum castings is available.

Note that all specifications are subject to change. Contact each manufacturer for details before ordering or buying.

 

Cylinder Head Innovations

The most common high-performance cylinder heads out there are the iron and alloy castings from Cylinder Head Innovations (CHI) in Australia, which are available from a number of sources in the United States in a wide variety of configurations. CHI has invested tremendous amounts of time in Cleveland head technology and come up with one of the best cylinder heads ever for the Cleveland and Windsor engine families. This cylinder head has gone to the Engine Masters Challenge and competed successfully on a grand scale. CHI tells me (at press time) no other cylinder head manufacturer has won the Engine Masters twice.

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CHI has taken the Cleveland head and made the most of its great potential with right-sized ports large enough to flow generous amounts of air and hot gases, yet small enough to make velocity. With velocity comes torque, and torque is what you want for street and weekend racing. If you’re going road racing, torque is what thrusts you out of turns and down straights. In drag racing, torque helps in coming off the line under hard acceleration. And with the right head, cam, and induction combination, torque hands off to horsepower at high RPM.

There are three basic types of CHI heads: 2V, 3V, and 4V. The 2V head, as its designation indicates, has the 351C- 2V (2-barrel) port configuration. The 4V head has 351C-4V port sizing. The 3V head has the airflow potential of the 4V head with 2V port sizing. It’s a great compromise between 2V and 4V.

Among CHI believers are engine builders Jon Kasse and Darin Morgan who have been able to massage these legendary cylinder heads and make a lot of power. CHI heads are completely manufactured in house from foundry to finished product. This enables CHI to maintain high quality standards. No fewer than five CHI heads are available for the 335-series Cleveland engine family. Within those head types, there are plenty of options.

CHI 3V Iron Head: The CHI 3V castiron Cleveland head is an iron version of the aluminum 3V with the same chamber, valve sizes, and port configurations. CHI conceived the 3V iron head for racing classes where aluminum heads are not permitted, yet you get the same benefits of the alloy head.

The 3V iron head can deliver upwards of 500 hp and comparable torque with standard displacement. If you dial in more displacement, horsepower and torque increase accordingly. The iron 3V head is available on a very limited basis for racers primarily. In truth, this is not a head for the average street enthusiast. Why order iron when you can shave weight (and heat) and have aluminum?

CHI Street Master 2V Cylinder Head: The CHI 2V 190-cc cylinder head works in perfect harmony with 351C-2V intake and exhaust manifolds. The 2V Street Master fl ows 300 cfm at .600-inch lift. Because the 2V head has the 3V (68 to 70 cc) or 4V (74 cc) chambers, you get great swirl and quench. With these features, detonation becomes a thing of the past. The 2V’s 220-cfm exhaust ports are designed to work with 2V or 4V exhaust manifolds and headers. Where the head meets the block, you get 5/8-inch deck thickness. These heads are available in stud or bolt-fulcrum configurations. They’re also available bare or assembled.

 

 

 

 

 

 

 

CHI 3V 185 cc: The 3V 185-cc cylinder head is in a unique class among Cleveland cylinder heads. Correct port sizing makes this cylinder head an exceptional pick because it is the smallest Cleveland head currently on the market. The 3V 185-cc head is well suited to stock-displacement bottom ends where you’d like to make up to 500 hp along with comparable torque. Intake ports are engineered to deliver the sweet combination of good low- and mid-range torque coupled with high-RPM horsepower. By downsizing the 4V port to 185 cc, you get the best of both worlds: lowend torque and high-end horsepower. The key to power is in high velocity at low-RPM ranges, which is where torque comes from.

CHI 3V 208 cc: The 3V 208-cc cylinder head was developed by Dave Storlien for the 2004 Engine Masters Challenge. The objective was 410 ci and revs up to 6,500 rpm with power in the 500- to 550-hp range. The 208-cc intake port features a minimum cross section of 2.300 inches with the tallest roof of CHI’s 3V head family. It has the most generous short-turn radius of all the 3V heads. The 208-cc intake manifold that goes with this head has fuel injection bosses cast in for port injection or nitrous. Intake port fl ow is a generous 314 cc at .650 inch. Exhaust fl ow is 223 cc, also at .650-inch lift.

CHI 3V 225 cc: This head replaces the older 218-cc design. It really is a serious street/race head for more than 400 ci and more than 600 hp. These 225-cc intake ports have a minimum cross section of 2.400 inches. What you get from these intake ports is shear volume—340 cfm at .700-inch lift; in the real world, 322 cfm at .600-inch lift. Exhaust fl ow is 219 cfm at .600-inch lift. In dyno testing, this has proven to be 740 hp and 640 ft-lbs of torque with 4.125 inches of stroke with a 6.125-inch rod along with 12.0:1 compression. Of course your results will vary.

CHI 3V 260 CNC:  The manufacturer says this is the “ultimate race Cleveland cylinder head.” What makes it a great head is revised intake and exhaust ports, some 370 cfm of intake fl ow, and CNC port design. Intake ports are .060 inch higher than the 3V 225 cc. At .600-inch lift, I witnessed 340-cfm intake and 223- cfm exhaust. At .800-inch lift (where this head really lives), I saw a whopping 370- cfm intake and 230-cfm exhaust. The 3V 260 CNC is not a street head because it is more at home at 760 hp.

 

 

 

Few aftermarket performance companies have done more for Cleveland engines than CHI. And few have spent more time making these heads even better than Jon Kaase of Kaase Racing Engines, which offers the Kaase C-400 head for all Clevelands.

 

 

CHI 4V 228 cc: This is the cylinder head for those who desire a factory-style casting. “Designed around our 3V 218- cc intake port, we spent many hours reshaping the entry of our port to accommodate factory and aftermarket intake manifolds,” CHI comments. “Careful attention was paid during development not to increase volume any more than  necessary to keep velocity high.” These heads are machined to accept 2.190-inch intake and 1.650-inch exhaust valves. If you want a larger exhaust valve, these heads can be machined to accept 1.710- inch valves at no extra charge.

 

Jon Kaase Racing Engines

Jon Kaase easily has the greatest understanding of Cleveland heads out there because he has been able to take the CHI head and massage it to where it   is the undisputed champ for airflow and power. Kaase has been working with CHI and other Cleveland cylinder head castings for years and knows how to shape ports to where they give up impressive numbers.

Kaase C-400: This head offers real Pro-Stock cylinder head technology, making it the most advanced Cleveland head ever to hit the market for racing. This may sound like a sales pitch, but it is not. When you study the numbers on the flow bench and in dyno cells, the C-400 is an unbeatable cylinder head for Cleveland and Windsor small-blocks alike.

The C-400 is available from Kaase in at least two CNC ported variations: the 2.850-inch, which means a 2.850- inch minimum intake port cross section, and the 3.100-inch, which means a minimum 3.100-inch cross section. The 2.850-inch 3V C-400 head is engineered to work with the 3.500-inch 4500 CHI intake manifold atop a 408-ci Cleveland.

 

The C-400 head from Kaase is the most advanced Cleveland cylinder head ever made. It is available in two CNCported versions. The C-400 2.85 has a minimum 2.850- inch cross section across its intake ports. The C-400 3.1 has a minimum of 3.100 inches. These generous intake ports offer in excess of 400 cfm at .700-inch valve lift thanks to Kaase’s handiwork. Ports are raised for improved flow tied to redesigned 45-cc combustion chambers. CHI induction works very well with the C-400 heads and is available with 4150/4160 and 4500 fl anges.

 

On the hot side, the C-400 brings improved exhaust scavenging thanks to its raised port angle. You’re going to need a custom piston with these heads with 1.200-inch compression height. CP Pistons offers a piston design (available from Kaase) that works with these heads. Relocated valve positions call for longer valvestems. “Although this cylinder head is designed with shaft-mounted rockers in mind, standard Cleveland roller rockers do work with this cylinder head and stud girdles need slight modification on the intake side for them to fi t,” Victor Moore of Kaase comments.

 

The Superboss is a good cylinder head for the money at roughly $1,600 in street form with 2.19/1.71-inch valves, 67-cc chambers, 205- cc intake runner, 105-cc exhaust, and 7/16-inch screw-in studs.

 

 

Of course the Superboss 351C head has a power partner in the Parker Funnel Web single-plane intake manifold, which is a perfect match to the Superboss head. The Parker/Superboss combination is engineered to optimize airflow between induction and intake port.

 

The Superboss 351C chamber offers great quench, minimal valve shrouding, and makes the most of its size. Intake ports flow 312 cfm at .600-inch lift out of the box and 341.2 cfm with optional Powerheads port work. Exhaust is 215 cfm out of the box at .660-inch lift and 240 cfm with optional Powerheads port work.

 

It is designed for more than 700 hp. The 3.100-inch port head is engineered for the new CHI 4.200-inch manifold. At .750-inch intake-valve lift, the 2.850 head fl ows 400 cfm. The result in actual dyno testing has been 800 hp and nearly 600 ft-lbs of torque.

The C-400 head has an all-new combustion chamber, not to mention revised intake and exhaust port layouts. What this means for you is the need for a custom piston with a specific compression height. CP Pistons has this custom piston already available. These heads are engineered for shaft-mounted rocker arms though you can go with stud-mounted rockers with a girdle.

 

Powerheads Performance Engineering

Ralph Pici of Powerheads has always managed to keep a low profile in the industry. However, he’s one of the sharpest engine builders and head porters I’ve ever worked with. Ralph understands how to get power through common-sense port and bowl enhancement—making the most of fl ow and knowing how it behaves.

Powerheads is well known for CNC port work on factory cast-iron heads. However, did you know Powerheads also sells new cylinder heads for the 351C and 351W engine families? The Superboss 351C aluminum cylinder head from Powerheads is available two ways: Street Boss and Track Boss.

Street Boss is an out-of-thebox aluminum cylinder head with 2.190/1.710-inch intake/exhaust valves and 67-cc chambers. Track Boss is the Street Boss head casting with CNC port  and hand-finish work plus stainlesssteel valves, dual valvesprings, 7/16- inch screw-in rocker studs and guide plates, and Viton seals. Both heads are a great value. The Street Boss is $1,595. For another $600, you get CNC port and finish work.

Powerheads Iron Side: Powerheads was originally founded in 1995 to do affordable CNC porting on factory iron cylinder heads including Cleveland. Of particular interest these days is the imported Australian Cleveland cylinder head with goodold- fashioned hot rodder port sizing and cutting. The Aussies had enough sense to match the 4V wedge chamber with 2V intake and exhaust ports to achieve a great cylinder head good from 2,500 to 6,500 rpm, which makes it the best factory Cleveland head out there. And Powerheads is the place to find it.

 

The exhaust clearly shows the difference between the 351C-4V head (top) and MPG CHI head (bottom). Though the 4-barrel heads have larger exhaust ports, they’re restrictive with that hump in the floor. The MPG CHI head has smaller exhaust ports, yet they’re not restrictive, offering better velocity and scavenging.

 

MPG Head Service enjoys a wealth of NHRA racing experience and success. The MPG 3V cylinder head for Clevelands is basically a CFI head with a tremendous amount of port work. These guys have performed quite well at the Engine Masters Challenge.

 

 

Scott Main of MPG placed the 351C-4V head (top) alongside the MPG CHI head (bottom) for a port comparison. The CHI head has “right sized” intake ports that afford you velocity and lower engine speeds, which translates to torque. These heads are happy at low- to mid-range RPM and go gangbusters at high RPM.

 

The North American 351C-4V head is a great casting if you intend to operate your Cleveland in the 3,500- to 7,500- rpm range. It is also a good cylinder head for a engine with more than 400 ci because you’re hauling more volume through those huge ports. The downside to the 351C-4V head is its exhaust ports, which have an ugly speed bump that disrupts fl ow and causes turbulence. Powerheads CNC port work improves 4V intake and exhaust fl ow if you’re going to operate at high RPM or move a lot of displacement.

Remember, any open-chamber Cleveland head is unacceptable because there’s no quench and these poorly thought out chambers are prone to detonation. It doesn’t matter how effective the smaller 2V ports are, it’s those awful open chambers that don’t get the job done.

So what about Aussie Cleveland heads from Powerheads? If you’re seeking a stock external appearance or are faced with a limited budget, iron Aussie heads are the best choice. A stock pair of Powerheads Aussie Cleveland heads retail for $1,195, or $1,695 CNC ported. In any case, all are fitted with stainless swirl-polished valves, hardened exhaust seats, screw-in rocker studs with guide plates, dual springs, new bronze guides, and Viton seals.

 

MPG Head Service/Cam Research Corporation

Many credible engine builders believe in CHI cylinder heads and are doing a lot with them. MPG Head Service/ Cam Research (outside Denver) is one of them. In 2006, MPG went to the Engine Masters Challenge with a 409-ci Windsor and made 680 hp and 480 ft-lbs of torque with MPG’s CHI 3V head. You might be tempted to ask, What does this have to do with Clevelands? The answer is “plenty” because bore and stroke are similar, along with rod ratio and cylinder head. The 409-ci Windsor (#31384715 Dart Block) made 680/480 using this proven 3V cylinder head recipe. That year, MPG accumulated 993.90 points right behind Jon Kaase Racing Engines with 1,043.20 points in First Place.

 

 

 

The MPG CHI head isn’t an extensively ported casting; instead it has a mild port and bowl work where it is needed to clean up airflow. MPG applies special thermal coating to intake runners to help reduce intake temperatures, which improves power because cooler air and fuel are denser. Exhaust ports are raised .400 inch to improve scavenging. MPG/ Cam Research takes the raw CHI 3V castings and fits them with its own stainless valves for better fl ow. Where the mixture becomes fire, a heart-shaped 64.5-cc wedge chamber features a good light-off and the absence of detonation thanks to great quench.

 

This is how far chamber design has come in 40 years. On top is the classic Cleveland wedge chamber. On the bottom is the MPG CHI high-swirl chamber, which is smaller with better quench. Couple this with excellent port design and massaging and you have the recipe for power.

 

The Scott Cook head isn’t a high-port head—yet it has the same basic port and chamber configuration as the successful CHI 3V head. This head accepts a 2.08/1.87-inch valve package for improved flow.

 

Scott Cook Motorsports

Australia has embraced the Cleveland engine family like no other place on Earth including the United States. Scott Cook is another Aussie with vision and enough imagination to conceive and cast his own Cleveland cylinder heads, which have CHI 3V-style chambers and port configuration while retaining the Cleveland’s external appearance. Bolted on, they look like a factory Cleveland 4V head; no one knows they are there once painted. If unpainted, they’re a great-looking casting to bolt on top of your Cleveland.

 

Here’s the new Scott Cook aluminum head, which is confi gured like the CHI head with minor casting changes to give it a more factory appearance.

 

This port and bowl work on a Scott Cook head has minimal or no valve shrouding and buttery-smooth CNC bowl work for improved fl ow. These ports fl ow well right out of the box. However, you can get even more improvement with fi nish work in the bowls.

 

The Edelbrock Performer RPM 351C head is engineered for the 351C, 351M, and 400 with 60-cc chambers, 2.05/1.60-inch intake/exhaust valves, Manganese bronze valve guides, 190-cc intake and 90-cc exhaust runners, and 5/8-inch-thick decks.

 

Cook claims with confidence these heads are performers right out of the box with no port work necessary. Of course that’s a matter of personal opinion and choice once your Scott Cook heads arrive. The company is not currently offering a 4V port; however, Cook ultimately expects to have one.

Somewhat confusing is that the Scott Cook head has what the Aussies call a “stuffed” 4V port instead of a full 4V port. The “stuffed” port is engineered with mid-range torque in mind.

The jury is still out on whether or not this is the best approach. So far in dyno and track testing, the Scott Cook Cleveland head has performed very well. On top of a 393-ci stroker, prototype heads produced 602 hp at 6,500 rpm and 505 ft-lbs at 5,600 rpm. These are baseline numbers from testing, but by no means the best they can do. There’s more testing to be done.

 

Edelbrock Corporation

Edelbrock has an affordable cylinder head for the 351C, 351M, and 400 engines. The Edelbrock Performer RPM for 335-series engines has well-thought-out “compact charge,” kidney-bean-shaped combustion chambers with intake and exhaust port runners based on the factory 351C-2V cylinder head. Instead of a dysfunctional open chamber, it has the good quench and squeeze of a 60-cc chamber that gets rid of destructive detonation for two reasons: great quench/antidetonation characteristics and great heat dissipation through aluminum, which keeps combustion temperatures down.

 

Exhaust port sizing is just right at 90 cc. This is basically the same size and positioning as the 351C-2V head for good velocity and scavenging. Headers bolt right up to the Edelbrock head.

 

 

 

The Edelbrock Performer RPM 351C has these cozy, kidney-shaped, 60-cc chambers for good squeeze and great quench. Valve size is 2.05/1.60 inches, which is on par with the factory iron head; however, it has better fl ow and port angle. An optimized spark plug location gives you adequate header clearance and puts the fi ring tip right in the middle of the action.

 

Trick Flow Specialties

There are many power players in the Cleveland head industry. As you might expect, Trick Flow Specialties could never stay out of this game because it’s just too much fun—taking the race-proven Cleveland head concept to the limit with a better alloy casting known as “Power- Port” available in two confi gurations: 190 and 225 cc.

Trick Flow says, “Ford’s 351 Cleveland was an engine that made big promises. The 2V version featured small port heads optimized for low-speed torque. The 4V heads, however, had huge ports that boosted top-end horsepower. What Ford did not do was make a version of the Cleveland that combined the torque of the 2V heads and the high-RPM rush of the 4V head design.”

Trick Flow responded to the North American Cleveland head’s shortcomings and is producing a great cylinder head that lives up to the proven Trick Flow name. The PowerPort Cleveland 190 and 225 cylinder heads, available in a variety of configurations, feature all the great nuances of Ford’s 351C-2V head, yet with a better exhaust port and compact wedge chambers that deliver outstanding quench and anti-detonation characteristics.

Exhaust ports are raised .100 inch for improved scavenging, yet they accept off-the-shelf headers and manifolds. Oil return drains are much improved over factory castings getting oil back to the pan as quickly as possible. All the lumps, bumps, and turns have been taken out of the intake ports for better fl ow. These high-tech castings are fitted with 7/16- inch rocker arm studs from ARP along with pushrod guide plates that are good to go. There is a choice of 1.530- or 1.460-inch spring installed heights. Viton valve seals deliver controlled oil flow to stems and guides along with excellent wear qualities.

 

Pro Comp USA

The Pro Comp Cleveland cylinder head is a copy of the highly successful Australian CHI 3V casting. Reviews are mixed about this cylinder head because it is inconsistent. Some like it; others would never buy another one. However, because it is affordable, it is a hot seller.

 

Because Trick Flow Specialties has always been successful at making Ford power, it’s no surprise it has come up with a pair of right-size cylinder head packages for the 351C, 351M, and 400 engines. There are two sizes: 190 and 225 cc (intake port volume). The 190-cc heads have 112-cc exhaust ports and 62- or 72-cc wedge chambers with 2.080/1.600-inch valves. Larger 225-cc heads have larger 115-cc exhaust ports with 60-cc chambers and 2.080/1.600-inch valves. Trick Flow stays conservative with valve sizing because that’s where the torque is.

 

 

 

Intake port sizing is generous with the Trick Flow heads and depends on what you want your Cleveland to do. If you’re running high displacement, such as a 408C or a 430+ 400, the 225-cc port and 60-cc chamber should make you happy. If displacement is conservative, consider the 190-cc port for better low- to mid-range torque.

 

 

It’s easy to feel good about Trick Flow’s low-restriction, 112- and 115-cc exhaust ports because they’re based on Ford’s 2V head. They have, however, been raised .100 inch to give hot gases more of a straight shot without causing header fitment problems. Bowls are nicely blended to reduce restriction and turbulence.

 

I decided to take a closer look at what people are doing with this head and what their experiences have been. Richard Holdener, respected author and technical writer, conducted a 400 dyno test with the Pro Comp head with remarkable results in Muscle Mustangs & Fast Fords Magazine. Holdener didn’t just install these heads right out of the box. He had Bryce Mulvey do a precision valve job on new Pro Comp heads, which involved port and bowl work that netted 348-cfm intake and 252-cfm exhaust. With greater airfl ow you can get more power with milder cam timing. And with displacement of 400 ci and higher, you get torque without the need for a lot of throttle.

When Holdener went to the Super- Flow 902 dyno with his tall-deck 400 topped with these Pro Comp heads and a CHI single-plane intake, he managed to get 529 hp and 506 ft-lbs of torque. The CHI single-plane was one of two manifolds used, the other being the Edelbrock Performer Air Gap dual-plane. With the Edelbrock dual-plane, he saw 489 hp and 502 ft-lbs of torque. Where his efforts really differed was where peak torque happened, considerably lower with the dual-plane thanks to its longer runners. (Holdener has proven the success of the Pro Comp head with port massaging and a good valve job. See Chapter 11 for more details on his efforts.)

 

Air Flow Dynamics

Australian Air Flow Dynamics (AFD) has been making cylinder heads for many years and is using that experience to produce a great one for the 335 Cleveland V-8s. AFD has engineered this cylinder head to produce a broad torque curve, which makes it an exceptional street and race head; good for up to 7,000 rpm. A high-swirl chamber is available in a variety of sizes depending upon your bottom end and compression needs. These heads are fitted with phosphorus bronze valveguides, 7/16-inch screw-in ARP rocker studs and Comp Cams guide plates, stainless valves, and hardened Durabond Diamond valve seats.

On the exhaust side, the AFD 2V Cleveland head has round ports for improved scavenging. Yet you can use existing off-the-shelf headers or manifolds with good compatibility. Intake ports have been extensively modified for improved fl ow. And it isn’t so much about volume, but more about how air and fuel fl ow from manifold into intake port. When you get intake and exhaust flow in synch coupled with the right cam profile, you cannot miss. Exhaust scavenging is just as crucial as intake fl ow if you want to make real power.

 

 

 

When AFD conducted initial dyno testing with these heads, it learned they made excellent street torque and horsepower. At 7,000 rpm, AFD witnessed 555 hp from 383 ci. Peak torque was 482 ft-lbs at 5,300 rpm. Induction was an Active 2V and 950-cfm carburetion. These numbers make the AFD a good street/strip head.

Another dyno test showed even better results with a 393-ci stroker: 666.1 hp at 6,900 rpm along with 534.8 ft-lbs of torque at 5,400 rpm. This was performed with a Parker Funnelweb 2V and 950-cfm carburetion.

 

Another item to check is valve-to-valve clearance. The minimum should be .060 inch to allow for thermal expansion when things get hot. You can stack two .030 gauges to verify clearance.

 

Regardless of what gasket manufacturers tell you about not needing head retorquing, you should always retorque your heads. Do it in three stages, and lube the threads with engine oil. Once the engine has had a good warm-up and break-in, retorque your cylinder heads.

 

When you’re setting up guide plates, don’t tighten them until you’ve mocked up the valvetrain (rocker arm, pushrod) and dialed in your geometry. Once you have good rocker arm geometry all the way through the complete range of travel, check pushrod to guide plate clearances and torque down the plates.

 

The AFD 4V head is a step up in terms of power and performance because it’s a nice balance of 2V and 4V heads. It delivers at high RPM with 4V-style performance while  acting more like a 2V at low RPM. What you get for your money is better exhaust fl ow thanks to AFD raising the port .080 inch, which enhances torque. Peak horsepower in testing has been 598.6 at 7,000 rpm, with torque topping out at 502.1 ft-lbs at 5,300 rpm.

 

Written by George Reid and Republished with Permission of CarTech Inc