Building A High Performance Boss Mustang 409 Engine - Big Boss Buildup
We Take A Look Inside MPG Head Service's Cleveland Head Small-Block Stroker
From the July, 2006 issue of Modified Mustangs & Fords
By Bob Moore, Jim Smart
Photography by Jim Smart
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.
This is the Dart cast-iron...
This is the Dart cast-iron 8.2-inch low-deck block (PN 313847) with four-bolt main caps, a priority main oiling system, and siamesed cylinder bores. This block is based on the old Boss 302 with an 8.2-inch deck, 4-inch bores, and 2.249-inch main journals. The block is sonic-checked and treated to a 0.250-inch overbore (that's 1/4 inch!), bringing bore size to a whopping 4.250 inches. With a stock bore spacing of 4.380 inches, this leaves a scant 0.130 inch between cylinders. But not to worry, Chevrolet buffs have been doing this with big-blocks for years.
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.
Pistons and rods become one...
Pistons and rods become one in the war on power. There's less piston in order to improve reciprocating weight, reduce internal friction, and increase displacement. This connecting rod is an MPG exclusive because it's actually a 5.470-inch Honda race rod ready for installation in your small-block Ford. This gives MPG a good rod ratio and longer dwell time at each end of the bore. Note the smaller 0.870-inch pin and 1.848-inch journal diameter. Why? To reduce internal friction and free up some ponies. This calls for a Scat special-grind steel crank from MPG with smaller rod journals. Relax-it's all about making intelligent power.
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.
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.
|Duration at 0.050 in: ||250-deg. |
|intake, ||252-deg. exhaust |
|Valve Lift: ||.744 intake, |
|Lobe Separation: ||106 deg. |
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.
|MPG at the EMC |
|Displacement: ||409 ci |
|Bore: ||4.250 inch |
|Stroke: ||3.600 inch |
|Average Peak Hp: ||658 |
|Average Peak Torque: ||584 lb-ft |
|Average Hp |
at 2,500-6,500 rpm:
|Average Torque at |
|531 lb-ft |
These numbers came from three back-to-back dyno pulls made after three warm-up dyno pulls.
Check out these CP-coated,...
Check out these CP-coated, custom, lightweight pistons. This is a flat-top, 0.043-inch ring-groove, low-friction slug with gas slots and high ring placement. Because MPG employs unique, low-friction connecting rods, we have an 0.890-inch piston pin. A thermal-barrier coating across the piston crown protects the piston and pin from extreme temperatures on top. An antifriction coating on the skirt reduces cylinder-wall friction to free up more power. Gas slots channel combustion pressures against the back of the top ring to improve cylinder sealing during wide-open throttle. The down side to low-friction rings is longevity. They don't last as long as wider rings. This is all about power in the short term and less about reliability in the long term.
When we place a stock 302...
When we place a stock 302 piston (right) next to the CP piston from MPG (left), the difference is clear. A stock piston gives extended life because there's mass and more load-bearing surface area. When it's time to make power, it isn't about longevity, but more about having less reciprocating mass and internal friction. We're also stuffing more displacement into the same bore, hence the mandate for less piston and different piston geometry.
Down under, there's an obvious...
Down under, there's an obvious difference in rod journal size-1.848-inches-less journal than we see with most 289/302/351W strokers...
...A smaller journal size...
...A smaller journal size reduces journal friction and frees up power.
We're knocking down the MPG...
We're knocking down the MPG Boss 409 for a closer look inside. Bob Moore lifts off the MPG 3V (does not mean three-valve) Cleveland head for an in-depth look at how to make more power with a set of cylinder heads. According to MPG, these heads are good for approximately 100 hp just bolting them on.
Let's start inside with close...
Let's start inside with close inspection of the 3V chamber. This Australian head gets the added benefit of CamResearch stainless steel 2.15-/1.65-inch valves. What's more, these canted-valve heads have intake ports downsized to 218 cc for greater flow (yes, greater flow). Exhaust ports are raised 0.400 inch for better scavenging. Where the heat gets hot, there's revised spark-plug positioning and a contemporary, heart-shaped, high-quench 64.5cc chamber.
The MPG 3V Cleveland head...
The MPG 3V Cleveland head is designed out of the box for 351C, 351M, and 400M engines. When it goes onto a 289/302/351W block, we have to plug the 351C coolant passages and make coolant passages for the 289/302/351W block. The 351C has a dry manifold void of cooling passages. The 289/302/351W has a wet manifold with cooling passages.
At a quick glance, the 3V...
At a quick glance, the 3V Cleveland head resembles the factory iron head. Closer inspection yields a lot of internal improvements that make it a better investment than 351C 2V or 4V heads. Standard are screw-in rocker arm studs and guideplates, larger stainless steel intake and exhaust valves, high-tech quench chambers, and better spark-plug positioning.
With the intake ports side...
With the intake ports side by side, it's easy to believe the larger 351C-4V ports (top) flow better.During extensive testing and massaging, Scott learned exactly the opposite is true. The MPG 3V head not only flows more air (343 cfm at 0.650 inch lift), but it also yields more velocity, which improves torque. Scott achieved this success with minor intake port massaging at the short turn and a space-age thermal coating that reduces temperature.
Chambers side-by-side are...
Chambers side-by-side are clearly different. The old-tech Cleveland wedge chambers (top) were the hot ticket in 1970, but not anymore if you want real power from your Cleveland or Windsor. Smaller, heart-shaped, high-quench chambers yield more power on light-off without pinging and opposing flame fronts. Look around the valves of the 351C-4V head and the MPG 3V. The 3V has less valve shrouding, which improves flow.
On the exhaust side, 3V ports...
On the exhaust side, 3V ports are smaller than the 4V, which also improves torque depending upon valve overlap. We're learning via Scott and MPG Head Service that port size isn't as critical as port geometry.]
When Scott was considering...
When Scott was considering the induction system, he decided to go with what he trusted most-the Ford Racing PN M-9424-B302 Roush single-plane manifold that was filled and ported on the intake side only per Engine Masters rules...
...Scott says he had a devil...
...Scott says he had a devil of a time finding this manifold and had to pay through the nose to get it.
Fine-tuning the 409 was straightforward...
Fine-tuning the 409 was straightforward because Barry Grant's removable sleeve Race Demon makes it easy to dial in flow. This is the Race Demon with 975-cfm sleeves.
The 1-inch Super Sucker aluminum...
The 1-inch Super Sucker aluminum carb spacer from MPG Head Service has a funny name, but it gives stellar performance....
This clever design improves...
This clever design improves flow between the carburetor and plenum by keeping fuel droplets in proper suspension, mixed properly with airflow. MPG took this to the Engine Masters Challenge and claims a 47-horse increase on naturally aspirated engines.
MPG opted for this electric...
MPG opted for this electric water pump from CSI Performance Products. An electric water pump doesn't consume the engine's rotary motion. It also yields reverse flow cooling, which pulls more heat out of a hot engine. The automakers have gone more to reverse flow cooling with good results.
Oil drainback is another power-robbing...
Oil drainback is another power-robbing issue because it drains back all over the crankshaft. MPG restricts oil return to the front and back of the block by plugging oil-drain holes at the block's center.
Scott stresses piston design...
Scott stresses piston design and its effect on power. He believes in reducing reciprocating mass, weight, and friction to free up power. This is a dished lightweight piston for greater displacement small-blocks. The crown is coated to protect the piston and pin. Coated skirts reduce friction.
Internal friction and weight...
Internal friction and weight can be found in connecting rods, too. Scott finds hidden power in smaller pins and journals because there's less friction and weight. This is a nice piece Scott used in the Boss 409-also available to MPG customers seeking big power gains.
Here's the 351W-based Dart...
Here's the 351W-based Dart block with four-bolt mains, siamesed 4-inch bores, thick walls, and more. If you want displacement upward of 490 ci, this is the platform for you. Imagine-big-block displacement in a small-block V-8.