Some enthusiasts may be intimidated by the DOHC layout that includes variable cam timing, but the reality is that swapping the heads wasn’t terribly difficult. The only real trick was making sure the cams were lined up properly.
The chain and sprockets all feature timing marks, and since we had previously swapped out the cams, this was still fresh in our minds. Off came the cam covers, damper, and front cover to allow access to the cam sprockets and timing chains. We took photos just to be sure, but we lined up the cams and crank at TDC—then we removed the tensioners, guides and cam sprockets. Next came the Comp cams from the stock heads, followed by the lifter/rocker assemblies (they were attached by a clip), and finally the stock head bolts.
The stock heads were removed and replaced by the CNC heads from JPC/RGR using the stock head gaskets. Since we planned on more boost in the future, we took the opportunity to upgrade the hardware to ARP head studs. ARP also supplied a set of main studs and damper bolt, but the main studs will have to wait until we upgrade the bottom end. With CNC-ported heads in place, we installed the Comp cams, lined up and installed the timing chains, and buttoned up the front and valve covers.
Once the stock intake manifold and throttle body were in place, we connected the JLT air intake and were ready to go. Once again, super-tuner Ken Christley from Kenne Bell was on hand to dial in the factory ECU using SCT software. After a brief warm up, we were rewarded with a significant jump in power.
Equipped with the stock heads, this combination produced 515 hp and 450 lb-ft of torque. After the installation of the CNC-ported heads from JPC, the peak numbers jumped to 545 hp and 475 lb-ft of torque. Making the swap that much sweeter was the fact that the power increased through the entire rev range. More power is good but more power everywhere is even better.
Though a head swap would be enough for most enthusiasts, we decided the Coyote needed even more power. Once again, the power came from Ford Racing in the form of a Boss intake manifold and matching throttle body. Adding the Boss intake upped the power output from 545 hp and 475 lb-ft to 571 hp and 449 lb-ft. Designed for high rpm, the Boss lost power compared to the stock intake up to 6,500 rpm, but where the stock intake fell off, the power curve offered by the Boss kept climbing, right up to 7,500 rpm.
The list of mods to our normally aspirated Coyote now included heads, cams, intake, throttle body, headers, air intake, and programming. Having exhausted the basic bolt-ons, you might think we would be done with the Coyote, but you’d be wrong.
Despite the fact that we have increased the power output of the Coyote by 123 hp and 45 lb-ft (from 448 hp and 405 lb-ft to 471 hp and 449 lb-ft), we want even more before giving the blower and turbo systems one more chance. We are inching ever so close to the 600hp mark in normally aspirated trim, so we have decided to take one last shot and get the 5.0L to produce an honest 600 hp.
Look for Stage 3 cams, a revised air intake, and even a custom intake manifold to help reach our goal. After that, we plan on running the Hellion turbo system, then following up with the Kenne Bell supercharger once again.
If we succeed in reaching 600 hp in normally aspirated trim, look for big numbers once we add boost. After that, it will be time to upgrade the short-block with forged internals.
Stick around—this killer Coyote is about to grab that Road Runner and ring his little neck.
6 The Stage 1 heads featured...
6 The Stage 1 heads featured stock valve sizes with a multi-angle valve job, but Stage 2 heads receive larger valves.
7 The JPC heads also featured...
7 The JPC heads also featured a valvespring upgrade. After witnessing valve float on our previous turbo testing, the stiffer springs were deemed mandatory for future testing.
8 After our baseline testing,...
8 After our baseline testing, off came the valve covers to allow access to the cams and cam sprockets.
9 Next came the intake manifold,...
9 Next came the intake manifold, throttle body, and injectors as one assembly.
10 Removal of the front cover...
10 Removal of the front cover revealed the cam sprockets, tensioners and guides. Shown are the passenger-side sprockets with the crank and cams set at 1 TDC.
11 The driver-side cam sprockets...
11 The driver-side cam sprockets were lined up as well. Note that the exhaust cam sprocket was driven by the crank; the intake and exhaust (rear) sprockets were connected by a small common chain.