Michael Galimi
March 1, 2008
Plan to take a weekend to remove the heads from your Two-Valve mod motor and replace them with a ported set from Fox Lake Power Products. It took Dez Racing a little more than a day, but swapping heads is standard practice for the ace technicians at the Massachusetts-based shop.

The vulnerable Two-Valve modular engine seems to be getting lost in the mix these days. We've been hitting the Three-Valve and Four-Valve modular markets pretty hard lately, so we thought we'd slide a Two-Valve mod motor Mustang into the garage for a little fun. The Dec. '07 issue of MM&FF featured a tech story on the Trick Flow Two-Valve intake manifold, and it was the perfect chance for us to take that car one step further.

We bolted the manifold on Keith Johnson's '00 Mustang GT, which was pumped up with a ProCharger P1SC blower (12 psi of boost). Other modifications to the GT included Anderson Ford Motorsport F-42 camshafts; a BBK 70mm throttle body; and Ford Racing Performance Parts shorty headers, x pipe system, and after-cat exhaust. The fuel system has been upgraded, and Mike Dezotell of Dez Racing performed a custom computer tune in this car. Holding the power is the job of a Tremec TKO transmission and Centerforce DFX clutch.

This combo with a stock manifold produced 441 rwhp and 413 rwtq. After adding the Trick Flow manifold, output results were 454 rwhp and 415 rwtq. We reestablished the baseline for this story, and Johnson's GT made 453--close enough to the 454 result we got three months prior. Torque was recorded at the same 415 rwtq.

The test results were great, and the intake picked up some power over stock. However, we thought it was better suited for something with a bit more airflow going through the engine. Sure, the test vehicle had a blower and cam-shafts, but the untouched stock heads were hurting the potential of the manifold. Others have tested the intake with different results, but our conclusion (and Dezotell's as well) was that it would work better in a package that has ported heads, cams, and a supercharger.

After kicking around the idea of adding heads to this car, we bit the bullet and called Ron Robart at Fox Lake Power Products. He said he had a set of castings sitting in his shop that were ready to roll and recommended Fox Lake's Stage 2 CNC port job and upgraded valvetrain. We prodded Robart for more information about what the company does to the Two-Valve castings. "We CNC-port the heads and assemble them with high quality parts," he told us. "We push quality, not quantity. The valves and hardware are from Manley. All ports and chambers are equal on the heads. Flow increases to about 225 cfm at 0.550 inch lift." The larger intake port would certainly take advantage of the larger ports in the intake manifold.

Pricing for Stage 2, including all of the bells and whistles that come along with it, is $1,795--you provide the cores. If you don't have a pair of heads to send in, then there is a $300 additional charge. Adding Fox Lake-ported cylinder heads will increase horsepower, a fact that has been proven time and time again over the years. It's money well spent. We could have made over 500 hp with this combination if the car had a fortified bottom end.

This oil-controlled hydraulic button applies pressure to the chain guides. Machie collapsed the button and used a pin to keep it compressed.

The blower output was left the same, meaning we kept the blower pulley and crank pulley identical in all testing. Boost usually drops off with the addition of larger/ported cylinder heads because air flows into the engine easier with less restriction. Boost is merely a byproduct of engine restriction. It's measured in pounds per square inch (psi). The blower output, however, will be the same between the before and after testing. A supercharger is a fixed entity in that the unit moves a specific volume of air at a given impeller rpm. Keeping blower speed identical is essential in a true A-B comparison. We're comparing stock heads versus ported heads, so why change the blower output? Upping blower speed would mean we changed two components instead of one.

The extra airflow proved to be worth 32 rwhp, as power increased from 454 rwhp to 485. The boost reading dropped a few pounds, as expected. The story behind the numbers is that the test car still has a stock bottom end. Dez could have pushed the power up a bit more, but he feared the bottom end would give up on us. We certainly would have loved to see 500 rwhp, but durability and reliability is paramount to Dez. He didn't buckle to peer pressure, returning Johnson's car intact and completely reliable. Overall, this car dyno'd at 365 rwhp with a stock engine and the blower. Power increased 120 rwhp with the heads, cam, and intake.

Nearly 500 rwhp is a stout street machine--one that could fry the tires at a moment's notice.

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