Mopar Engine Challenge - Fire-Breathing Big-Blocks

The Top End
Mopar racers and engine builders alike know that Indy heads make power. For this reason, Mopar Engines West chose Indy's 440-1 cylinder heads for their build. The long-valve design of the Indy heads means intake ports can be enlarged significantly, thereby increasing flow. Exhaust ports are also raised, and port volume of the Indy heads is significantly higher than anything produced by the factory. Ferrea valves were used with Comp 946 valvesprings and were actuated by Indy's 1.6 ratio rocker arms. The most significant modification to the cylinder heads, however, was the port work performed by engine builder David Timmon's daughter Angie, who had been to Joe Mondello's cylinder head school and spent some 40 hours hand porting not only the intake and exhaust ports, but also the combustion chambers of these heads. During the post dyno inspection it was apparent the modifications worked, as burn patterns on the piston tops and in the combustion chambers indicated a very efficient burn. The Indy 440-2 intake manifold was also ported, as well as the spacer between the carburetor and the intake. A Holley 1250-cfm race Dominator took care of the fuel-mixing duties, and an MSD distributor was modified in-house to achieve timing curves suitable to both the rpm range of our contest and the relatively high 12:1 compression of the engine. Overall, this engine impressed us with power, efficiency, and reliability, and we congratulate Mopar Engines West for their impressive performance.

Speed-O-Motive, West Covina, Ca
Speed-O-Motive, based in West Covina, California, has been involved in the automotive aftermarket since the inception of hot-rodding during the '40s. They are known for providing powerful and reliable high-performance engines, and their entry in this year's contest was no exception. The Speed-O-Motive shop is equipped with state-of-the-art equipment, and they are able to handle any of their customer's needs, whether building a stock small-block or an exotic, stroked big-block.

For this year's challenge, the guys at Speed-O-Motive decided to try something a little different. As the only entry to run Brodix cylinder heads, Speed-O-Motive showed us there are many ways to attain killer power from the Mopar wedge engine. As expected, this engine ran great right out of the box with no tuning necessary.

The Bottom End
Like all of this year's competitors, Speed-O-Motive utilized a well-seasoned block for their engine challenge build. Their '74 vintage block was fully machined on Speed-O-Motive's Rottler equipment. After align-boring the block and clearancing it for the stroker crank, the cylinders were bored and honed with torque plates, and the main webbing was machined for aftermarket, Milodon main caps. A Speed-O-Motive brand, 4.15-inch stroke crankshaft was combined with I-beam rods and JE forged pistons to complete the rotating assembly. Since this engine would be using Bodix B-1 cylinder heads, the piston's valve reliefs had to be recut due to the nonstandard valve location in the B-1 heads. Total Seal gapless rings were used to seal the cylinders. Clevite bearings were coated in-house and used for both the rods and mains. A Milodon oil pan, 11/42-inch pickup, and windage tray were combined with a Melling high-volume oil pump to handle the lubrication duties. A solid-roller camshaft was custom ground to take advantage of the B-1 heads strength, airflow on the top end. While considered "top secret," we learned that duration at 0.050 for this grind is a healthy 280-degrees intake and 296-degrees exhaust. Lobe lift measured 0.500-inch intake and 0.490-inch exhaust, equating to a valve lift of 0.850- and 0.833-inch, respectively. Unfortunately, the crew at Speed-O-Motive had limited time to optimize this combination and could have shown even bigger numbers by experimenting with other cam grinds, but still managed some very respectable numbers.