The 2007 Mopar Muscle Engine Challenge
If you've followed our previous engine challenges you're already familiar with the basic rules. Each engine must qualify by making three, nonscored dyno pulls during a 45-minute period. Tuning and repairs may be made during this time, as long as three pulls over the full span of 3,000 to 7,000 rpm are made. After the qualifying pulls, the builder will be given 10 minutes to inspect his or her engine before making the dyno pulls that will be scored for the competition. Three required scored pulls must be made in the second 45-minute session, and tuning is allowed between pulls as long as three complete dyno pulls are made during the 45 minutes. We then take the scored pull with the best combined peak torque and horsepower, and factor the cost of the parts into the power for a horsepower-per-dollar factor. Manifold vacuum will be used as a bonus rating, and one point will be awarded for each inch of manifold vacuum at 1,000 rpm. So if the competition is close, the engine with the most vacuum will win the position.
Since there are literally hundreds of block and cylinder head
combinations for the small-block Mopar, we decided to open the rules up a bit for this year. Engine displacement will be limited to 410 ci, and the block must be a production, cast-iron block or replacement block. The crankshaft must be either cast or forged steel, and only steel connecting rods will be allowed. No lightening of the crankshaft will be allowed. Pistons must be catalog, off-the-shelf units with factory size ring grooves. since there is no restriction on compression ratio, engine builders will likely push the limits based on the Rockett Brand 93 octane pump gas we'll be using for the challenge.
Because there are so many cylinder head options for the small-block Mopar, and in the interest of big power numbers, we decided to be less restrictive with this year's cylinder head rules. Instead of providing headers for the competition, we're requiring the engine builder to supply his or her own headers to match the cylinder heads
on their engine. We're still only allowing production, Mopar-style cylinder heads, and we won't allow welding or epoxy modifications to the heads, but otherwise cylinder head selection is up to the engine builder. We look forward to a diverse selection of cylinder heads as builders will certainly utilize varied techniques to gain an advantage.
We're limiting induction to a maximum of 1,000 cfm this year, which should be plenty of fuel and air for these small-blocks to make big power. There is no limitation on the number of carburetors, so dual quads or six-pack induction is legal. Power adders, however, will not be allowed since our plan is to show how much power the small-block can make in a normally aspirated form. While we're pretty sure most builders will use large, single-plane intake manifolds for maximum power, we can't help but wonder if anyone will use stock induction to keep costs down.
If you're going to attend the Mopar Nationals in Columbus this year, plan a trip by the Mopar Muscle trailer to see all the entries in this year's contest. Engine builders will be on hand to discuss their techniques and can likely answer questions about your next engine project as well. Last year, our display drew quite a crowd as some of the best engine builders in the country eagerly shared their engine-building knowledge with anyone who was interested.
After the Mopar Nationals, the challenge engines will be delivered to Comp Cams where they will remain until they are placed on the dyno in late September. Comp has a great facility, and their hospitality during previous engine challenges has been second to none. Every year our challenge engines have made more and more power on Comp's dyno, and we hope this year is no different. Even with fewer cubes to work with, we won't be surprised to see horsepower numbers well above the 700 mark.
If you've run a small-block Mopar in one of your cars
, then you certainly know the potential of this great engine. If you're a devout big-block or Hemi enthusiast, this year's contest might change your mind about the potential of the Mopar small-block. As our contest gets underway, be sure to stay tuned to future issues where we'll not only tell you who won, but also go inside each engine in depth, outlining the combinations that worked, as well as those that came up a little short. Also, if you're in the market for a new engine, be sure to contact one of our engine builders. These guys know Mopar engines and can certainly help with your next project.