2006 Mopar Muscle Engine Challenge - We Have A Winner!

Speed-O-Motive - West Covina, CA

Since the inception of hot rodding, Speed-O-Motive has been known for providing reliable power to its customers. The Hemi Speed-O-Motive brought to last year's challenge made the second highest combined power score, and the most power of any engine equipped with a single carburetor. This year, August Cedarstrand and the guys at Speed-O-Motive decided to once again show that reliable power can be made with somewhat unconventional parts. By using Brodix B-1 original cylinder heads, they knew they would be sacrificing some torque down low, but felt they could make up for it at the higher rpm range of our test. Their engine was strong and reliable right out of the box, making all its dyno pulls without incident and finishing in sixth place.

Speed-O-Motive certainly lived up to its reputation as a leading provider of reliable power. Their 500-inch wedge fired up immediately and sounded right at home on Comp's dyno, idling smoothly and completing its required dyno pulls without so much as a change in timing. This engine could easily have been dropped into a car and run with no further tuning. In fact, the only tuning technique used by engine Speed-O-Motive's August Cedarstrand was to remove the air filter for the judged portion of the contest, freeing up a few extra ponies. Rather than going for peak numbers, the guys at Speed-O-Motive impressed us again this year with a smooth-running, trouble-free entry that was ready to compete right out of the box. In fact, the dyno pulls went so smoothly it gave us time to have a little fun with this engine in the form of nitrous oxide. For anyone who doubts the durability of a factory 440 block, we'll make the following statement. Speed-O-Motive's 500-inch wedge made some 980 hp and 890 lb-ft of torque by using a 300hp ZEX nitrous-oxide system and held together for multiple pulls, showing no signs of wear upon teardown. Be sure to follow along as we go inside this engine and see the fun we had with nitrous oxide in a future issue.

Promax - Indianapolis, IN

Tying for seventh place in this year's contest was the Promax entry, which unfortunately failed to qualify for the judged portion of the engine challenge. During its first dyno pull, the Promax engine began making a rattling noise, and builder Ben Gorman chose to abort the pull. Removing the valve covers, the cause of the noise was apparent. The end bolts holding the rocker shafts to the heads were too short, allowing the threads to be pulled from the heads and bending the left rocker shaft in the process. While this did keep Promax from officially finishing the contest, the guys at Comp quickly provided another rocker shaft and longer bolts so repairs could be made. At the end of the competition we allowed Promax to make an additional dyno pull, which netted them a respectable, though unofficial, 587 hp and 595 lb-ft of torque. The mechanical problem was unfortunate since this engine was built on a strict budget, and the Promax entry certainly would have placed better had it made its required runs.

MRL Performance - Jackson, MI

Mike Liston of Jackson, Michigan's MRL Performance could have won this year's engine challenge if his engine just would have made it to the 7,000 rpm upper limit of our contest rules. This entry was definitely built using economical parts, and if it would have made the required pulls at the required rpm, it would have been hard to beat. The only engine to use a hydraulic, flat-tappet camshaft, and using Edelbrock's Performer RPM cylinder heads, this engine was designed to win the contest based on cost, not peak power. During the first pull the engine sounded smooth and made decent power, but only turned 6,900 rpm, 100 rpm shy of the contest rules. As additional pulls were made, and as the valvesprings warmed up, rpm peaked at 6,800, preventing Mike from moving to the judged portion of the contest. Even so, power was a respectable 472 hp with torque at 507 lb-ft.

We were all scratching our heads as to why this engine wouldn't turn 7,000 rpm during the contest, but Mike discovered the problem later at home. His wife had videotaped his dyno runs, and when he reviewed the video he noticed the carburetor's secondaries weren't opening. Heading to the shop, he quickly pulled the vacuum actuator apart and found the vacuum port blocked, which had kept the secondaries from opening. If not for this problem, the MRL entry would have certainly placed higher, if not won our engine challenge.