Big-Boost Bullet - D.S.S. Racing Two-Valve 4.6 Modular Engine Build

Horse Sense: D.S.S. has forged its reputation in the industry with more than 26 years of experience, including its Outlaw Super Stock and Pro Stock efforts, along with the success of racers Bob Kurgan, Steve Ross, Bob Cook, Keith Kohlmann, and Chris Griswold.

One of our main objectives at 5.0 Mustang & Super Fords is to keep our readers abreast of the upgrades for late-model 'Stangs of all years. As many of you know, just about every point of a Fox, SN-95, New Edge, or S197 Mustang is open territory for making changes. Showing you the way to make these improvements is what we're all about.

When it comes to modular performance, the Four-Valve 4.6 is the powerplant that's been lauded for the last 10 years as the baddest OEM engine, especially the supercharged versions of the Cobra engines in 2003-2004. Unfortunately, all mod-motor 'Stangs could not be equipped with these engines, and we like to give love to the underdog Two-Valve engines from time to time, especially when it comes to performance.

The Two-Valve engines in Mustang GTs struggled in the power department between 1996 and 1998, which is fairly common knowledge these days. We also know that an improved cylinder-head design with reshaped intake ports made things a lot better for our favorite ride in 1999, and the aftermarket also started producing a wider variety of performance equipment for 4.6s. Ported heads, bigger cams, larger throttle bodies and plenums, high-flow exhaust components, electronic tuning, and, of course, power adders, quickly became the performance modifications that '99-'04 Mustang owners were eager to make in their quest for more horsepower. Today, a turbocharged, nitrous-injected, or blown Two-Valve's dyno numbers can just about mirror or, in some cases, better those of a stock '03-'04 Snake.

The big deal is that making the underdog Two-Valve perform well can be done without mega-dollar expense. Spending a few grand in bolt-on horsepower for your '99-'04 GT, when compared with the cost of buying a Cobra, a Mach 1, or even an older modular Cobra, is where it's at these days.

For those of you who haven't been following our reports, we've made quite a few bolt-on changes to our daily driven, once-bone-stock '02 Mustang GT over the last year. Many aspects of the car's performance, such as handling and braking, acceleration, driveability, horsepower, and torque, have improved as a result of the upgrades. Installing a ProCharger Stage II P-1SC supercharger system was our last major change ("Beyond Bolt-On," June '06, p. 78]. We think you'll agree the results of this upgrade-383 hp and 372 lb-ft of torque at the rear tires-are outstanding, as we added more than 125 rear-wheel horsepower for less than four Gs. Keep in mind, our GT still sports stock heads and a stock bottom end. With regard to our power gains with the blower, a few of you might ask, "That's all?" In our case-yes, that's all. We're aware that a shade over 410 rear-wheel horsepower is close to the threshold of tolerance for a stock, Two-Valve mod motor on pump gas. We've received e-mails from '99-'04 owners, however, who have pushed the envelope and claim power numbers in the 450s with race fuel. While we certainly could have dialed in the 410 pump-gas, ragged-edge horsepower during our tuning session, we elected not to so that boost-influenced horsepower would not lead to a premature demise for our 'Stang's engine. Piston and/or rod failure are imminent when you get too aggressive with a power adder on a stock 4.6. When these parts gradually or suddenly expire as a result of high cylinder pressures, ring seal and compression deteriorate and you end up with either a supercharged slug or a 'Stang in need of a tow truck. We're all about stepping up, but there are proper ways to do it.

When the time comes to pump up your supercharged Two-Valve engine program and go far beyond the unofficial, 410-horse, pump-gas parameters of a stock engine's internal components, the first step is to set up your 'Stang with an engine that's built to handle the pressure of boost. Clearly, OEM iron blocks and cast crankshafts are good and are not the primary point of failure in most cases.

We're almost ready to go to the next level with our resident 'Stang by adding a bigger blower and shooting for 600 pump-gas, driveable rear-wheel horsepower, so we checked with the folks at D.S.S. Competition Products in St. Charles, Illinois, for guidance on building a good foundation for our new power.

"Optimizing ring seal is the key to making big power in a forced-induction application," says Tom Naegele, one of the co-owners of D.S.S. He's also our point man for the Level-10 race-prepped, D.S.S. Super MODular 4.6, Two-Valve short-block ($3,699.95) that will replace the 45,000-mile factory engine. We decided to retire it or use to resuscitate another tired 'Stang while it's still of sound body and function.

The D.S.S. Level-10 CNC block preparation process is unique and thorough, with more than 35 blueprinting operations performed on every block. Blueprinting an engine involves doing what's necessary from a machining and assembly standpoint to put together the engine according to predetermined specifications, based on exactly what D.S.S. or the customer wants the engine to be. Tom says that only seasoned Romeo and Windsor 4.6 iron blocks are used for the modular engines in his company's product line. He adds that the Level-10 (and Level-20 for pushrod motors) prep work D.S.S. does is the essence of achieving great ring seal in the high-horsepower bullets they offer.

We recently visited the crew at D.S.S. and got a firsthand look at how a Super MODular 4.6 comes together. This short-block was founded on Ford's Romeo block (PN M-6010-D46) and D.S.S.'s brand new, CNC-ported, big-valve cylinder heads ($1,499.95) that feature Anderson Ford Motorsport cams (PN F62; $629), Jesel's new hydraulic camshaft followers that work with OEM lash posts (PN OCS-82100; $1,599.20/set of 16), and the all-new Typhoon aluminum Two-Valve intake manifold by Professional Products (PN 54060; $675). This will be our foundation for making the progression into the big leagues of modular performance. There is a lot more exciting information about this project, which we'll bring to you in future issues. Read on for a look at how D.S.S. prepares and builds its Super MODular 4.6.