Back in the day, you could add a set of aftermarket heads, a bigger cam, and an intake manifold on a pushrod 5.0L and effectively double the power output. Although that sounds impressive, the base motor made a whopping 225 hp. (It’s amazing what was considered powerful in the ’80s and ’90s.) So what effect do heads and cams have on the latest 5.0L?
In 2010, MM&FF got its hands on an ’11 GT to customize for the SEMA show; this also gave us the ability to test parts. Our AMSOIL GT has been a great research and development tool, testing out many “first” products for the Coyote in the past 15 months.
Recently, the idea of adding a set of ported heads and larger aftermarket camshafts came up as a potential story, and the debate started on how the DOHC 5.0-liter would react. One side argues that improved airflow equals increased power. The other side states that Ford did such a great job maximizing the platform’s efficiency, there isn’t much to gain—at least, not when the cost is taken into account. After all, the engine operates above 100-percent volumetric efficiency through most of the rpm band.
Due to the complexity of the...
Due to the complexity of the installation, Chris Jones and the crew at Blow-By Racing started by unbolting the K-member, then they lifted the car off of the engine and transmission. This way everything is accessible, and saves time and knuckles.
We were left with a few questions. How would improved airflow through the already stout heads affect power and torque? What potential was there with the combination of larger cams and the variable cam timing? And how would it all be affected by boost? Well, there’s only one way to find out!
Our trip into the unknown started with a call to Total Engine Airflow (TEA). We have used TEA for some custom porting and cylinder head repair work in the past, and the Tallmadge, Ohio-based company is second to none. With a fresh set of stock castings, TEA went to work designing a CNC program for the Coyote heads.
When it came to camshafts, we had options. With Coyote camshaft technology still developing, we could have used a set of regrind cams, which are just that—stock camshafts reground with smaller base circles on each lobe allowing you to gain increases in lift and duration. The reduction of camshaft base circle usually means the lash adjusters need to be shimmed to make up for the material lost during machining on the camshafts. Our other option was to wait for a set of new billet shafts, and after talking with Comp Cams, we decided to do that.
1. Total Engine Airflow (TEA)...
1. Total Engine Airflow (TEA) sent us a set of CNC-ported Coyote cylinder head castings.
2. The ported castings aren’t...
2. The ported castings aren’t hogged out due the high level of efficiency from the factory. They are massaged to improve airflow, and the runners are only 5cc larger.
3. You can see the stock...
3. You can see the stock runners aren’t much smaller, but the port work is evident in the flow numbers.
4. TEA also installed a set...
4. TEA also installed a set of heavier valve-springs. The beehive-style springs will be available from Trick Flow Specialties (PN TFS-16801-32) and have 80 in-lb of pressure on the seat. Pressure increases to 180 pounds when opened 1 inch.
5. The stock camshafts measure...
5. The stock camshafts measure 12mm lift (0.472-inch) on the intake side and 11mm lift (0.433-inch) on the exhaust side. The advertised duration is 260/263 degrees respectively.
6. With the front cover removed,...
6. With the front cover removed, the timing chains and tensioners are unbolted. The timing chains are similar to the older Four-Valves.
7. Our GT only has 1,331...
7. Our GT only has 1,331 miles on the odometer, and it was evident when the stock heads were removed. It looked like it was just assembled, with pronounced crosshatch marks and barely any carbon on the pistons. We could even see all of the laser-etched markings on the pistons from Ford.
8. Once everything was cleaned...
8. Once everything was cleaned and free of oil and coolant, we were ready to begin reassembling the engine. Cometic Gaskets sent us a set of its multi-layer steel (MLS) gaskets for the new DOHC 5.0-liter.
9. The gaskets have three...
9. The gaskets have three layers of steel, and once compressed under the cylinder heads, have the same thickness as the stock head gaskets, which means compression will not be affected.
10. Jones and Rob Vargo lower...
10. Jones and Rob Vargo lower the CNC-ported casting on to the stock short-block, and tighten everything with a set of head bolts from Ford Racing Performance Parts. The heads are torqued in four steps: 18 lb-ft, followed by 30 lb-ft, then two rounds of 90-degree rotation.
11. After applying a generous...
11. After applying a generous amount of assembly lube, Jones lowers the new Comp Cams into position. The new shafts measure 0.492-inch lift on the intake cam and 0.453-inch lift on the exhaust side. Duration is 228/235 at 0.050 respectively.
12. Comp Cams also sent is...
12. Comp Cams also sent is a set of its Cam Phaser Limiters to ensure there are no piston-to-valve clearance issues. The limiters are precisely machined pieces of aluminum designed to limit the amount of travel in the cam adjusters.