Michael Johnson
Associate Editor, 5.0 Mustangs & Super Fords
December 1, 2007
Does this engine look capable of making 300 hp at the wheels? We thought the Cobra intake would hold things back, but that was just us. We know what most NMRA Factory Stock cars have done to them to make more than 300 hp at the wheels, but they have lightweight engine components and other tricks our test subject didn't have. We were using an off-the-shelf Steeda no. 18 camshaft, while most combos exceeding 300 hp to the wheels utilize custom cam designs. We were hesitant to allow ourselves to think this combo could make the power we desired. As usual, we were wrong.

Horse Sense: Steeda Autosports says its no. 18 camshaft-the one we used in this article-is ideal for making horsepower on a streetable 5.0 with or without a supercharger. Although originally developed for supercharged applications, Steeda's testing found it beat out a lot of aftermarket cams in power production for naturally aspirated combinations as well.

When it comes to naturally aspirated horsepower goals with our Mustangs, one of the main targets is the 300hp mark. We're not talking about engine dyno numbers, we're talking power to the wheels-that's what matters most. The 300hp mark has always been difficult in the Fox Mustang arena, and some of us fall short even with the best-laid plans in place. With a supercharger, turbocharger, or nitrous, surpassing that number is relatively easy, but doing it the natural way can be difficult. We say any goal worth setting is worth going after-or something like that.

When Patriot Performance released its Freedom Series 5.0 heads, Blow-By Racing looked forward to putting them through the paces and seeing if 300 hp was a reality with the new castings. Before now, Patriot stuck to the modular field, along with some LS-style Brand X castings. With its new Freedom as-cast heads, Patriot is making inroads into the pushrod Ford market. Judging by the numbers, these heads are going to free up a few more ponies from our Ponies.

Patriot Performance's Freedom head is a new casting with several designs available for small-block Fords. The ones we're featuring sported a five-angle valve job, 185cc runners, 60cc combustion chambers, 2.02/1.60 valves, 0.550-inch hydraulic springs, steel retainers, and 31/48-inch rocker studs. "Just expanding our market," Patriot's Gunner Bowlin says when asked why a 5.0 pushrod head was added to the lineup. "We're bringing a new model to the market with excellent performance at a good price." Speaking of price, Blow-By lists the heads at $895.95, bringing them in at a lower price point than most, if not all, aftermarket heads.

Blow-By Racing's Chris Jones knew that just adding the heads wouldn't get us to our 300hp goal, so he threw in a Cobra intake, Prime One 1.6 roller rockers, a Steeda Autosports no. 18 camshaft, and BBK long-tube headers. He didn't quite make the 300hp mark with the stock throttle body, mass air meter, and air intake, so Blow-By replaced those items with a 70mm throttle body, a 73mm mass air meter, and a JLT Performance cold-air kit. These products helped us meet our goal. Read on to find out how we did it.

Though we were most interested to see the new Patriot Performance Freedom Series heads, we matched them with tried-and-true 5.0 Mustang performance veterans such as a Cobra intake, Prime One 1.6 roller rockers, a Steeda Autosports no. 18 camshaft, a new timing chain, new pushrods, new lifters, and ARP head bolts.

The new Patriot Performance Series 5.0 head is ideal for street Mustangs, thanks to its 185cc intake runners, 60cc combustion chambers, a five-angle valve job, and 2.02/1.60 valves. The 0.550-inch valvesprings are perfect for street-style hydraulic-roller cams, especially for the Steeda no. 18 camshaft we're using here. This cam features a 0.480-inch lift with 1.6 roller rockers, a 220-degree intake duration, and a 226-degree exhaust duration. A 112-degree lobe separation further exhibits mild street manners.

Speaking of the cam, Blow-By Racing's Chris Jones is seen here installing the Steeda no. 18 camshaft. Use either a cam or assembly lubricant to make it easier. As you can see, this seasoned short-block is free of its stock valvetrain. The new lifters are soaking in oil as we install the cam, so they'll be somewhat pumped up when we get the engine running. We didn't mess with any cam timing tricks; we installed it straight up. With 143,000 miles on the short-block, we knew it was time for new lifters...

...and a timing chain. Chris added a double-roller version to make sure the combination would hold proper timing.

Once the Steeda cam and new timing chain are installed, the lifters are inserted into the lifter bores. They use tie-bars and a guide retainer to keep them in place, so don't forget to reinstall those items. It's a good idea to insert the lifters before adding the heads; it's a lot easier that way.

With the lifters, tie-bars, and guide retainer installed, we can now get everything set to put in the Patriot Performance Freedom Series heads. First, the block's deck must be thoroughly cleared of any imperfections so the head will firmly seal against the block. Then we add the head gaskets. Most head gaskets are marked "front" so they can't be installed backwards. Notice the two locating dowels at the front lower and rear lower head bolt holes. Sometimes when removing the stock heads, these pins stay in. Make sure they're in the block when the new ones are installed. They'll make it easier to set the heads in place.

While the timing chain cover is installed, Chris torques the heads to spec. There are several different lines of thought when it comes to the torque specs. When torquing the heads, begin from the two center bolts and work out on each side. Move to the right, then back to the bolts on the left of the center two bolts, then torque the outer bolts in the same sequence. The recommended torque specs are 70 lb-ft for top and bottom, but begin at around 45 lb-ft and progressively work up to 70 lb-ft on each bolt.

Aftermarket roller rockers offer greater valvetrain stability compared to factory stamped steel rockers. The stamped steel rockers are known for flexing under heavy loads, and you don't want that at high rpm. Working with individual cylinders, rotate the engine using the crank damper bolt until each valve is closed. The rocker's corresponding lifter is riding on the camshaft's base circle, not on the lobe, meaning the valve will be closed and fully seated. Tighten the rocker while turning the pushrod with your fingers. When you can no longer turn the pushrod, the lifters are preloaded. Tighten the poly lock on the rocker and repeat the procedure on others. If you're confused by this at all, it's best to have someone with roller rocker installation experience around.

With the valvetrain set, Chris moves on to ready the engine for the Cobra intake. He uses a threaded rod to put the gaskets in place, and he puts RTV silicone around the water passages for further sealing capabilities. The threaded rod not only keeps the gaskets in place, but they'll help us immediately align the intake in the right spot.

As he did in high school, Chris uses a cheat sheet to help him with the intake torque sequence. Just as the heads are torqued in sequence, the intake has a special torque pattern and specs, which are more involved, requiring a caption the size of the NFL's substance-abuse policy. We don't have that many pages, so consult a Haynes or Chilton's manual for the sequence.

Similar to many other head/cam/intake stories we've done, the stock valve covers wouldn't clear the aftermarket roller rockers. Since it was getting late in the day, we used a pair of sheetmetal valve covers, which not only clear the rockers, they look great doing it. You can also see we've reinstalled the fuel injector harness, and much of the front accessory drive system. We didn't break open the A/C system for this operation, either. We moved the compressor and lines out of the way to gain access to the engine.

Before adding the Cobra upper intake, we checked any clearance issues with the sheetmetal valve covers. With just a gasket between the upper and lower, the valve covers would contact the throttle cable so we had to use a spacer to make everything fit.

Make sure all cables, electrical wires, and harnesses are out of the way so you can lower the upper intake into place. Locating studs aren't necessary for installing the upper intake, but if you choose to use them, only do so in the passenger side front and rear-most bolt holes. If you have someone helping you install the upper, you most likely won't need any locating studs in order to install it in a timely manner. Don't tighten all the bolts until they're safely threaded into the lower.

Moving underneath, it's time to add the BBK long-tube headers. These headers were on the car prior to the dyno-testing, but stock exhaust manifolds were put on the car for our baseline numbers. In order to install the headers, we had to loosen the motor mounts and jack up the engine. While one person is feeding each header up from the bottom, someone else needs to be up top to thread in the front- and rear-most header bolts to prepare everything for the header gaskets.

We've tightened the motor mounts, installed the headers and H-pipe, added new spark plugs to the Patriot Performance heads, and reinstalled the distributor and spark plug wires. All that's left to do is reinstall the air intake system, add fluids, and throw the car back on the dyno to reward our hard work with increased horsepower. Here, Chris is installing the stock intake tube, mass air meter, and a K&N conical filter. We didn't quite reach our 300hp mark with the stock air intake setup, so after we left, Chris fitted the car with a JLT Performance cold-air kit, a C&L Performance 73mm mass air meter, and a 70mm throttle body.

Let Freedom Ring

  A B C D DIFFERENCE
A vs. D
RPM Power Torque Power Torque Power Torque Power Torque Power Torque
2,500 125 262 118 248 130 273 131 276 6 14
2,750 142 272 139 266 156 298 159 303 17 31
3,000 160 281 161 282 177 309 182 319 22 38
3,250 171 277 178 287 194 313 202 327 31 50
3,500 187 282 196 294 213 320 222 333 35 51
3,750 199 279 216 302 228 320 {{{240}}} 336 41 {{{57}}}
4,000 206 271 228 301 244 321 256 338 50 67
4,250 210 260 244 301 261 {{{323}}} 277 342 67 82
4,500 212 247 258 301 274 320 291 339 79 92
4,750 214 236 267 296 275 304 294 325 {{{80}}} 89
5,000 208 218 267 281 281 295 297 312 89 94
5,250 {{{200}}} 200 264 264 276 276 298 297 98 97
5,500 185 176 261 250 271 259 288 275 103 99
5,750 165 153 246 225 260 239 272 250 107 97

A: Baseline test utilizing stock engine with underdrive pulleys, off-road X-shape crossover, a K&N conical filter, and Flowmaster mufflers with dumps.
B: Added Patriot Performance Freedom Series heads, a Steeda Autosports no. 18 camshaft, a Cobra intake, Prime One roller rockers, and BBK long-tube headers with corresponding off-road X-shape crossover.
C: Added a BBK 70mm throttle body, richened air/fuel mixture, and readjusted roller rockers.
D: Added a JLT Performance cold-air kit and a C&L Performance 73mm mass air meter.

When Blow-By Racing's Chris Jones approached us about doing this article, the GT we used for the test featured a Cobra intake, BBK long-tube headers, and an off-road X-shape crossover. We wanted to see what our H/C/I combo was worth versus the stock heads, cam, and intake, so we asked Chris to install a stock 5.0 intake, exhaust manifolds, and an off-road X-shape crossover. During both segments of dyno testing, the exhaust ended with a pair of Flowmaster mufflers utilizing dumps in front of the rear axle. In its stock configuration with the exhaust mods, underdrive pulleys, and a K&N conical filter, the car was surprisingly strong, making 214 hp and 282 lb-ft of torque. True to form, the horsepower peak came about in the 4,700-rpm area, while respectable torque came online around 2,200 rpm and stayed there.

After we installed the heads, cam, intake, and long-tube headers, our first dyno pull was less than we were hoping for with 267 hp and 303 lb-ft of torque. The engine seemed to struggle to build rpm so we started tuning and making mechanical adjustments. Chris adjusted fuel pressure to richen the mixture, and he adjusted the roller rockers. Horsepower improved, but we were running out of tuning options. Chris decided to open the intake tract by adding a BBK 70mm throttle body. These changes started us in the direction of 300 hp with 281 hp and 323 lb-ft of torque.

If a little is good, then a lot must be better, right? Chris further opened up the intake tract by adding a JLT Performance cold-air kit and a C&L Performance 73mm mass air meter. The addition of the cold-air and mass air pushed us over the edge, making 302 hp and a nice flat 344 lb-ft of torque. You don't see it in the dyno chart, but that's because the 302 hp made its appearance at 5,100 rpm on the graph. Mission accomplished.