When most of us imagine our favorite Mopar street engine, we generally tend to think of stroker big-blocks, small-blocks, or Hemis as being the best choice for big power. And while huge displacement and big torque numbers make for impressive dyno sheets and imposing burnouts, there are also disadvantages to building a huge engine for the street. Fist, the parts for a large-displacement V-8 engine are expensive so the cost per cubic inch can grow exponentially as displacement rises. Second, the big torque produced by large-displacement engines is often way more than the car’s drivetrain, suspension, and traction can stand, resulting in tire spin and broken parts while being outrun from a stoplight by a 318 Duster. And third, as we’ve shown in the 2011 AMSOIL/Mopar Muscle Engine Challenge, when it comes to horsepower per cubic inch, smaller engines seem to have an advantage.
Each year of our annual dyno contest, we challenge engine builders from around the country to build powerful Mopar engines that can run on Rockett Brand 93 octane unleaded gasoline, while staying within the rules of our competition. This year, we featured the big-block Chrysler, and engine builders had to remain within a parts budget of $5,500 to avoid a stiff penalty of ten horsepower per every $100 over the budget. The winner of the 2011 contest will be determined by the engine making the highest horsepower per cubic inch, while remaining within our allotted budget and the official rules, which are outlined on our website, www.moparmusclemagazine.com. We were impressed with the creativity of this year’s competitors, resulting in a wide variety of parts used by the engine builders to create their big-blocks.
In last month’s issue, we gave you the details about the dyno pulls of the four engines that were run on Monday and Tuesday during our week of competition, and this month we’ll highlight the engines that ran on Wednesday and Thursday. And while this year’s contest wasn’t without incident, causing the LaRoy Engines entry to be run out of the pre-determined sequence, all of the engines featured in this month’s issue made their dyno pulls thanks to the help and generosity of the other competitors and the staff at Comp Cams.
Norwood, North Carolina
HP Engines is a newcomer to...
HP Engines is a newcomer to the AMSOIL/Mopar Muscle Engine Challenge, bringing a 406 cubic inch big-block with Edelbrock aluminum cylinder heads. This engine made 608 horsepower, for a score of 1.50 horsepower per cubic inch.
We try to feature a variety of professional engine shops in our annual dyno contest, and were impressed by the engine entered by H P Engines of Norwood, North Carolina. As a foundation for his big-block, engine builder Hollis Page chose a factory Chrysler 400 block and a stock 383 forged crankshaft for a displacement of 406 cubic inches. Using Eagle connecting rods and Icon forged, flat-top pistons, the necessary machine work was performed in-house by Brett Gibson and Hollis himself, then the engine was assembled by engine builder David Kluttz using Edelbrock heads, an Edelbrock intake, a Bullet flat-tappet camshaft and Harland Sharp rocker arms. Appearing to have stayed within budget, this is a solid big-block built with quality parts.
On Comp’s Superflow engine dyno, the H P Engines entry fired immediately and sounded crisp during its warm up period. Needing to make three qualifying dyno pulls during a 45-minute qualifying session, engine builders Hollis Page and David Kluttz set the timing at 36 degrees total advance and made their qualifying pulls back to back before checking valve lash and increasing the jet size in their Holley 950 HP carburetor. During their judged session, the 406-inch big-block was revved to 7,300 rpm and jet size was again increased. On their second scored pull, the H P Engines entry made its best power of 608 horsepower at 7,300 rpm, for a factor of 1.50 horsepower per cubic inch. With time left in their session, the H P Engines team performed an intake swap to a tunnel-ram, but the engine actually lost a little power, a testament to the team’s initial combination.
The H P Engines big-block...
The H P Engines big-block sounded great on the dyno, and engine builders Hollis Page and David Kluttz got busy tuning their 406-inch entry to make its qualifying pulls. Knowing these pulls wouldn’t affect their score, rpm was kept at 7,000, which was below the engine’s peak.
With time left after their...
With time left after their third required scored pull, a tunnel-ram intake was installed on the engine. Power was down slightly, and this big-block made its best numbers with the Holley 950 mounted on an Edelbrock single-plane intake. At 608 horsepower on 93 octane fuel this is a stout big-block, and we congratulate H P Engines for their 1.50 horsepower per cubic inch score.
Keeping careful track of their...
Keeping careful track of their dyno pulls and tuning, the H P Engines team checked and adjusted their valve lash, then increased jet size for the scored session.