Building A High Performance Boss Mustang 409 Engine - Big Boss Buildup

Imagine being able to make 680 hp and 530 lb-ft of torque from a low-deck 289/302ci block. Most people would say this is impossible, but MPG Head Service and CamResearch in Englewood, Colorado, did it, in cooperation with Primedia's Popular Hot Rodding magazine, at the '06 Jeg's Engine Masters Challenge, held at Bill Mitchell's Hard Core Racing on Long Island, New York. Think of the Engine Masters Challenge as dyno racing with a twist. It isn't just about who can make the most power, but how you make that power in order to become "World Champion Engine Builder.

The Jeg's Engine Masters Challenge is an arena for the best engine builders in North America. It isn't easy. Mandatory displacement is 410 ci, and the engine must run on 92-octane fuel through 3-inch pipes and mufflers. Competition is divided into three groups for the first round of dyno racing. The top two engines from each qualifying round move on to final competition. With a score of 993.90, MPG Head Service came in Fifth in the Top Six from a field of 50 top-drawer participants from around the country. First Place, which went to Jon Kaase Racing, netted a score of 1,043.20.

It wasn't easy for MPG to enter a Cleveland-head, 302-based engine in this competition. Remember, the mandate was 410 ci. How do you stuff 409-410ci into a 289/302 block? We're going to tell you. Because MPG wanted to remain loyal to its mainstream 302-inch customer base, it was determined to build something based on this engine instead of the 351C or 351W. MPG contacted the rules committee and told them what it wanted to do. Remarkably, the committee agreed, and MPG went to work.

Just about any savvy engine builder can throw together something that can make 600 hp and 450 lb-ft of torque. The greatest challenge is where and how you make that power. Where do horsepower and torque begin and end? How useful is your power on the street? If power happens only at 6,000 rpm, your engine isn't very useful on the street, let alone the track. For an engine to be truly competitive, power needs to happen and last across most of the engine's operating range. This means useful power from 2,500 to 6,500 rpm.

Meet Scott Main of MPG Head Service and CamResearch. Three and one-half decades ago, $50 a month bought a lot of car. With lawn mowing and paper-route money, 14 year-old Scott bought his first car-a '69 Super Cobra Jet Mach 1 with the Drag Pack option. Even before he could get a driver's license in the state of Colorado, this relentlessly determined kid would talk to anyone who would listen into driving him to the racetrack in order to compete at the drags. That gut determination paid off when he won NHRA's World Championship in 1978.

Shortly after accomplishing such an incredible feat, Scott opened MPG Head Service and CamResearch, taking his passion and channeling it with specialty parts for Ford V-8s such as made-to-order intake manifolds, heads, and more. CamResearch was his avenue for custom-ground cams and valvetrain components for most Ford and Chevrolet applications. Scott has several patents to his credit, which means he's always thinking of new ways to make or improve performance. Suffice it to say we're not surprised he did so well at the Engine Masters Challenge.

The MPG/CamResearch Ford small-block seen here doesn't use a factory block, but it employs the same deck height, bore spacing, and oil-pan rails as the 289/302ci Ford. What's more, it will fit into just about any Ford you can think of. At first glance, it looks like an aluminum-head small-block Ford with some fancy bolt-ons. Closer scrutiny reveals a motive to Scott's madness, and insight into how productive power is made.

How does anyone get 409 ci from such a small package? Most folks stop at 347 or 355 ci using a stock block. Based on MPG's popular 355 and 377ci Boss stroker engines and modern Dart block technology, here's how Scott squeezed 409 ci into a 289/302-size block.

Cleveland 4V Vs. MPG 3V
Let's put the factory 351C-4V head alongside the MPG 3V head and compare. It's apples and oranges because the MPG 3V Cleveland head is a clean sheet of paper casting for Clevelands and Windsors alike. It's simply better than a factory iron 351C-2V or 4V head. The 3V yields technology that was unavailable in 1970. The trend in cylinder heads is toward smaller, more efficient heart-shaped chambers with plenty of quench area for improved combustion. This takes the ping out of hard acceleration and makes the most of the fuel/air charge. Behind the wheel, it means more power without engine suffrage.

Would you believe the MPG 3V intake port flows more air than the larger 351C-4V ports? Scott tells us improving port geometry does this. Not only has MPG improved intake flow with this head, but it has also improved velocity, which provides more torque. MPG achieves this with five-axis CNC port work-improving the short-turn radius and offering a better valve job at the same time.

To keep port velocity high, the finished intake runners aren't extensively modified at all. They remain a lot like they arrive from Australia. Scott hand-finished one short-turn radius and intake bowl, which improved flow during development. He took this information, digitized it, and made it part of his CNC programming. MPG coats each intake port with a special thermal coating to reduce intake charge temperature-which means a denser mixture and greater power. Scott learned he had to do little to the chamber. Exhaust ports have been raised 0.400 inch to improve flow.

Camresearch
Scott went with a mechanical roller cam from his own CamResearch company. A mechanical camshaft makes sense when we're going to spin it high and don't want the irregularities of a hydraulic roller cam. Pro Magnum 1.7:1 roller rockers from Comp Cams are also used. Here's the straight dope on this Engine Masters cam from CamResearch.

MPG opted for this rocker arm stud girdle from Jomar, which is mandatory for camshafts with fast ramps and high spring pressures. This keeps the valvetrain stable and safe.

Scott adds that seat-to-seat duration is short and lifter acceleration is fast. This means fast open and a lot of time at near full lift to fill the bore with the densest mixture possible. This means power across a broad band.

These numbers came from three back-to-back dyno pulls made after three warm-up dyno pulls.