BOSS 302 Upgrades: Ford Racing Cobra Jet Manifold Kit and Cams

When Ford unleashed the BOSS 302 nameplate on the Mustang world in 2012 they created the ultimate driving Mustang. With improved horsepower and a chassis capable of putting much more expensive cars to shame, the BOSS was one of the best engineering exercises in Mustang history.

Most BOSS owners are like any other enthusiasts, they plan to drive their Mustangs hard and are looking for the best bang for the buck with the best engineered upgrades available to them. With that in mind, Ford Racing created several upgrades for the BOSS engine that build upon the strengths of that car while adhering to strict Ford production standards.

We recently had a chance to follow along as one owner sought to create the ultimate naturally aspirated BOSS. The results from a few bolt-on parts and a new tune are impressive, to say the least.

The complete group of parts ordered for this round of upgrades include new intake and exhaust cams, a Cobra Jet intake, dual-bore 65 mm throttle body, and Cobra Jet Cold Air Intake.

Breathing Deeper

You’ve no doubt heard the comparison of an internal combustion engine to an air pump. The more air you can inhale and exhale, the more efficient and powerful the pump becomes. Part of what gave the BOSS its high-revving ability and more horsepower was its unique intake manifold. This high-rise, long-runner piece has become a favorite of enthusiasts and flows more air than the standard 5.0 intake found on the Mustang GT.

The BOSS intake is not without some drawbacks. According to Ford Racing’s Dave Born, this intake still had to meet many production standards, like packaging constraints for the assembly line. As a result the BOSS intake had to make a few compromises before it ever made it down the assembly line. That doesn’t mean it’s not a good intake, but sometimes you can do better when you don’t have to produce a part for mass consumption. That’s where the Ford Racing Cobra Jet intake manifold, part number M-9424-M50CJ, picks up what the BOSS had to leave behind.

An evolution based around the BOSS 302 intake concept the Cobra Jet intake manifold is a no compromises intake for high winding 5.0 engines. Ford Racing says the manifold is tuned to provide peak power at 7,750 rpm.

“With the Cobra Jet intake we’re dealing with enthusiasts who are bolting this part on at home or in a shop environment. That solves several of the packaging constraints of the BOSS manifold,” says Born. “This lower volume intake allows us more flexibility with the design.”

The Cobra Jet manifold is an evolutionary product that began with engineers installing a larger oval or dual-bore style throttle body inlet onto a BOSS intake for testing. From there the project continued to evolve with engineers seeking to find other ways to improve on the airflow of the BOSS.

The Cobra Jet manifold features larger intake runners and is devoid of the interference in the bell mouth on the rear runners for cylinders four and eight that were mandatory for the production line BOSS piece. There’s also no interference from the injector pockets with the intake runners on the Cobra Jet intake.

Side by side it’s easy to start spotting the differences between the BOSS intake and the Cobra Jet.

With the Cobra Jet intake we’re dealing with enthusiasts who are bolting this part on at home or in a shop environment. That solves several of the packaging constraints of the BOSS manifold. -Dave Born, Ford Racing

Born tells us that the Cobra Jet intake was designed with the BOSS engine in mind. This intake was designed, engineered, and tested by the same team that worked on the BOSS 302 program. The intake also had to meet all of Ford’s critical testing requirements leading to a piece that has OE level quality fit, finish, and performance while delivering aftermarket level performance gains.

Bringing the air into that Cobra Jet intake is a Ford Racing 65 mm Cobra Jet Billet Aluminum Throttle Body, part number M-9926-CJ65. Machined from billet aluminum and featuring big 65 mm twin inlets, this throttle body is capable of inhaling a massive 1,517 cfm. It’s ready to bolt on without the need to transfer the factory electronics. The unit is calibrated for stock idle air flow characteristics and also uses stock throttle body gearing to prevent bind or wear.

That throttle body breathes through a Ford Racing Cobra Jet Cold Air Intake Kit, part number M-9603-M50CJ. This air intake has a huge 102 mm air inlet diameter to feed that hungry throttle body. It also uses a high flow air filter and molded plastic housing to supply that filter with plenty of fresh air.

Left: Disassembly to install the new cams and intake manifold begins by removing the front accessories and water pump. Center Left: Next the crank pulley needs to come off. Remember, this is a one-time use bolt. Center Right: All of the bolts for the timing cover are then removed. Right: With everything out of the way the cam covers and timing cover can be carefully removed.

Putting The Bump In The Thump

Upgrading a BOSS to be the ultimate naturally aspirated example wouldn’t be complete without revisiting the camshafts. To that end Ford Racing supplied us with a set of intake and exhaust cams to liven up things in the horsepower department. Both of these cams measure 13 mm gross lift with 263 degrees duration on the intake cams and 290 degrees duration on the exhaust. These cams are available from Ford Racing, the intake cam set is part number M-6550-M50BINT, and the exhaust cam set is part number M-6550-M50BEXH.

The Ford Racing BOSS intake and exhaust camshaft upgrades feature 13mm gross lift and 263 degrees duration on the intake cam, 290 degrees duration on the exhaust.

The cams underwent the same engineering standards, and were developed by the same team as the original BOSS components. -Dave Born, Ford Racing

The same Ford engineers who developed the BOSS production cams continued development of larger duration 13 mm cams even though they weren’t going to make it into the production BOSS engine. Born says these cams were taken through the same engineering development process as any set of production cams. In the end they were thoroughly tested in Ford’s climate controlled dyno lab that ensures consistent results during testing.

According to Born, the exhaust cams were developed with increasing BOSS performance in mind. These cams also underwent the same stringent development process as the intake cams. Engineered to maximize naturally aspirated BOSS engine output without the need for additional internal modifications these cams unleash the horsepower within the BOSS’s Roadrunner engine.

Top Row: Left to Right: The timing chain tensioners and guides are removed followed by both long timing chains. Bottom Row: Left to Right: The camshaft phasers are responsible for operation of the Ti-VCT system and are removed in the next step to be transferred to the new camshafts. These bolts are also one time use only and will need to be replaced.

Full Phase Retention

The Ford Racing camshafts allow for full retention of the cam phaser driven Ti-VCT system. What this means for enthusiasts is that there are no limiters being installed in the cam phasers. On the street and the track this translates to OEM level response down low and the engine’s ability to then go up high bridging the gap between a high winding race engine and a torquey street machine.

“The cams underwent the same engineering standards, and were developed by the same team as the original BOSS components,” says Born.

Born tells us that like the intake cams the exhaust cams were designed to make full use of the stock Ti-VCT cam phaser system. This means that these cams don’t give up low or mid-range performance in favor of higher peak numbers. These cams also don’t require the use of limiters which restrict the operation of the phasers.

“We developed these parts to build the ultimate naturally aspirated BOSS while still giving great driving characteristics and engine response. We didn’t want a product that required changing other internal components in order to function or put the engine in danger of the valvetrain and cams getting out of control.” This strict adherence to Ford’s OE level engineering standards has yielded a product that is as bolt-in as any cam can possibly be.

With the phasers out of the way each cam has its caps removed and is then removed from the engine.

Making It Thump

Installing this hardware sounds like a daunting task. It is true that a dual overhead cam engine is more complex than the old cam-in-block units. However, with the majority of the parts on top, this swap is no more difficult to perform. In fact after our experiences with modular engines over the last 18 years we’d rather swap the cams in an OHC engine than in the older OHV units any day.

The oil filters in the end of each camshaft must be transferred to the new cam.

Parts List

  • M-9926-CJ65 65 mm Cobra Jet Billet Aluminum Throttle Body
  • M-9424-M50CJ Cobra Jet 5.0 Intake Manifold
  • M-9603-M50CJ Cobra Jet Cold Air Intake Kit
  • M-6550-M50BEXH BOSS 302R Exhaust Cam (pair)
  • M-6550-M50BINT BOSS 302 Intake Cam (pair)
The stock BOSS intake manifold, cam covers, and timing cover on both sides of the engine were removed. Next to come out are the long timing chains followed by the camshaft phasers. With the phasers out of the way the cams can then be removed.

With the new Ford Racing cams properly lubricated they were then installed and the rest of the installation was the reverse of removal. The biggest thing here is taking time to ensure all the timing marks are aligned properly during assembly. We capped things off with the Cobra Jet intake manifold, new big bore throttle body and Cobra Jet specific air intake.

Top Row: The new cams are lubed and then installed on each bank one at at time. With the cams in place and cam covers back on the car the Cobra Jet intake was set into position. Bottom Row: Left: With the intake in place the new twin bore 65 mm throttle body is bolted on. Center Left: All of the electrical connections, vacuum and PCV tubes are connected. Center Right: The mass airflow sensor is transferred into the Cobra Jet Cold air intake. Right: The Cobra Jet Cold Air Intake is assembled and installed on the car.

Tuning

With Rhyne Cunningham tapping the keys, we put the modded BOSS on the rollers at Cunningham’s Motorsports to see what kind of power numbers the engine would make. The only other modification to our engine is a set of Bassani long tube headers, H-pipe, and cat-back exhaust. Ford Racing recommends long tubes with the use of these parts to take full advantage of the air being moved out by the new exhaust cams.

Left: The coolant system is purged of air under pressure and checked for leaks. Center: The engine ready to fire up and test on the dyno. Right: Strapped to the dyno at Cunningham Motorsports the BOSS is ready to make more power the old fashioned way -without a power adder.


We baselined the car at 433.5 hp and 354.0 ft-lbs of torque to the rear tires on Cunningham’s Dyno. When Cunningham was done the BOSS had picked up 39.5 hp and 15.2 ft-lbs of torque at the rear tires for total power of 473.0 hp and 369.2 ft-lbs of torque. Those gains start coming on strong at 4,400 rpm and stay with the engine all the way to redline. Above 5,000 rpm the difference becomes even more dramatic as the cams take advantage of the improved airflow of the Cobra Jet intake and throttle body to make bigger power. Ford claims the Cobra Jet intake is tuned to peak at 7,750 rpm and that’s apparent from our dyno results, although we think the engine could have easily gone to 8,000 and probably continued to make power.

With everything in place we took the car out for a test drive. This BOSS is now badder than it ever was, and probably one step closer to how the Ford engineers behind the project envisioned the car would perform.

Article Sources

About the author

Don Creason

Don Creason is an automotive journalist with passions that lie from everything classic, all the way to modern muscle. Experienced tech writer, and all around car aficionado, Don's love for both cars and writing makes him the perfect addition to the Power Automedia team of experts.
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