Horse Sense: Centerforce says the definition of DYAD is "two units treated as one; a couple; a pair, or combining power of two."
After owning one of the first Coyote swap cars on the planet for a couple years, it was time for a new project car. I became intrigued by the ’01 Bullitt model, and after just missing out on a Highland Green version (I really wanted that one), I found a black example that fit perfectly into my budget.
Going from my Coyote-swap ’94 Cobra to a stock-engined ’01 Bullitt was quite the step down in power. However, the Bullitt was a much nicer starting point than the Cobra. The Bullitt was the perfect cruising Mustang. It was slow, which kept me out of trouble, it handled amazingly well thanks to a Maximum Motorsports Grip Box suspension, had amazing brakes thanks to a Brembo package up front, and most importantly, it was stock and reliable.
Even with all that, as I mention, it was slow. I mean, dog slow. But that was OK for a little while because we... had... a...plan. It probably only felt really slow because the Coyote Cobra made 400-rwhp with a 7,000 rpm shift point. The Bullitt’s little 4.6 Two-Valve couldn’t even come close to those numbers. Something had to be done, but what were our choices?
When Ford Racing announced its new 5.0-liter short-block, we jumped at the chance to get one under the Bullitt’s hood. But what would we pair with the short-block? We toyed with the idea of doing a Four-Valve head conversion, but wanting to avoid complications, we opted out of that and decided to use a Two-Valve loaded with the best parts available. As such, we went to Trick Flow for one of its top-end kits.
Our goal was to prove a point—that a Two-Valve could be a viable option. We wanted to make, as KJ would say, big steam with a and show you didn’t need a Coyote swap to make real N/A power.
Were we able to prove our point? You’ll have to read on to find out.
1. We were chastised on Facebook for running through a parts store having a sale on silver paint, but trust us, when you see the finished installed shot, you won’t see all silver. However, this is how the 5.0-liter stroker looked just prior to throwing it on the trailer, and hauling it up to David Piercey’s Mustang Performance a few miles north of our Tampa, Florida, office. Dave (D2) Squire and I assembled the top end of the engine here at the Tampa office before taking it up to Dave (D1) Piercey’s shop. Here you can see we’ve added the Trick Flow Track Heat heads (TFS-51910004-M44; $1,149.97 per) and Street Burner intake (TFS-51800000; $869.97) to Ford Racing’s new 5.0-liter modular short-block (M-6009-A46X; $5,299). Instead of reusing the factory cam covers, we used Trick Flow items there as well. For headers, you can see we went with BBK Performance’s 15⁄8-inch long-tube headers (15410; $599.99), while a Trick Flow 75mm throttle body (TFS-24075; $189.97) sits up top. We hadn’t received the new PA Performance alternator bracket as part of it, and as you'll see, the bracket flips the alternator around at the front of the engine. Before tackling something like this on your own, it's a great idea to have installation instructions not only from Trick Flow, but also Ford, to make sure you don't miss or mess up any steps. You don't want to wipe out an engine because you missed a step, torque sequence, or the like.
2. This is what we started with, Ford Racing’s M-6009-A46X 5.0-liter short-block. Ford Racing uses an ’05-’10 aluminum block with a 3.572-inch bore and an Eagle 3.75-inch forged stroker crank to arrive at 5.0 liters of displacement. This short-block also features Eagle H-beam connecting rods with ARP 2000 bolts, Mahle forged aluminum pistons, and a high-pressure oil pump. The rotating assembly is neutral-balanced, and the short-block is ready for your top end, whether it be a Two-, Three-, or Four-Valve combination. Ford Racing dyno’d several different combinations with this short-block, including a Three-Valve combo with an FRPP 2.3 supercharger and Hot Rod cams, and it made 748 horsepower and 667 lb-ft of torque at the flywheel. The dyno number we were more interested in is the one featuring the parts we used for this bolt-on experiment. Those numbers were 424 horsepower and 416 lb-ft of torque at the flywheel. The compression ratio for the engine Ford Racing tested is 10.78:1, and we used the exact same parts so our engine's compression ratio should be in that neighborhood, as well.
3. Trick Flow’s Twisted Wedge Track Heat 185 cylinder heads for Ford’s 4.6/5.4 modular are designed to go right in place of factory Two-Valve heads. Since the Trick Flow heads are the only aftermarket choice, they’re pretty much the only game in town, and we’ve seen them used on both fast street cars and racecars alike. Since we wanted more performance than could be offered with PI castings, we chose the Trick Flow Twisted Wedge Track Heat 185 heads. These heads feature a CNC-machined, 44cc combustion chamber volume, 1.84/1.45 valves, a 185cc intake runner volume, and a 93cc exhaust runner volume. They arrived to us fully assembled with valves, beehive-style springs, 7-degree locks, powdered-metal valveguides, and a three-angle valve job.
4. Before installing the heads, you have to decide the heads’ orientation. In other words, figure out which side each head will be installed on. The heads aren’t side-specific until you add the oil plugs. These plugs are critical for oil flow and pressure through the heads, and must be installed, or you’ll have oil leaks, and the valvetrain won’t receive proper oiling. It’s way easier to install these plugs into the heads while they’re off the engine.
5. Keeping in mind the cylinder heads’ orientation, we installed the heads on top of the Ford Racing head-changing kit’s MLS head gaskets. Like the heads, the head gaskets are side-specific. Since we were starting fresh with a new engine, we didn’t need them, but Trick Flow includes rubber sleeves to help place the head bolts on the heads when installing them with the engine in the car. There’s a specific torque sequence for the heads, which is covered by the Trick Flow instructions.
6. Ah, yes, we wanted the mean sound that comes with adding rowdy cams. Since we were adding the Trick Flow heads, we thought the perfect match for them would be Trick Flow’s Track Max hydraulic-roller cams for 4.6/5.4 Two-Valve engines ($569.97). These 0.550-inch-lift cams have a basic operating range of 1,500-to-5,000 rpm with a 228 intake/230 exhaust duration at 0.050-inch lift and a 112-degree lobe separation. All of the above help to maintain everyday driveability and stock-computer compatibility. These cams work with both stock PI heads, and of course, Trick Flow heads. They made our Bullitt sound unlike any other Two-Valve. It’s worth adding these cams to a stock engine just for the sound alone.