The Hemi engine is synonymous with top-end power, so Speed-O-Motive took advantage of Stage V aluminum cylinder heads for their build. Porting and polishing were performed in-house to maximize flow before installing stainless-steel Ferrea intake and Manley exhaust valves. Manley springs and titanium retainers were also utilized to keep the valvetrain stable. Stage V roller rocker arms were matched with T & D rocker shafts to actuate the valves. Combustion chambers were coated with a thermal barrier coating designed to reduce detonation, allowing for slightly higher compression while using our Rockett Brand 93 octane fuel. When it came to camshaft selection, Speed-O-Motive chose Competition Cams to custom grind their flat-tappet bumpstick. Not wanting to give away any secrets, they would only say that lift was in the ".550 to .650-inch lift range." Based on the idle qualities and performance of this engine, it's our guess that lift was closer to .650 inch than .550 inch. Comp solid lifters were matched to the camshaft, which was spun by a billet timing set with a Torrington-style thrust bearing. Topping off this potent combination is a Stage V single-plane aluminum intake with a 4500 series carburetor flange. A Barry Grant Race Demon carburetor handled the air/fuel mixing duties and an MSD Pro-Billet distributor fired the mixture.
How did it perform? How about 722.6 hp and 618.8 lb-ft of torque! This engine definitely has power to spare for a street application and should carry a mildly prepped race car into the nines with ease. While the use of specialized coatings did increase the cost to build this engine, the added protection should ensure long engine life.
We congratulate August Cedarstrand and Speed-O-Motive for their fourth place finish and for making more power than any other single-carbureted entry in our challenge.
Ross Pistons and Eagle connecting...
Ross Pistons and Eagle connecting rods were some of the tough parts utilized in the Speed-O-Motive entry. Specialized coatings were also used throughout the engine, both as friction enhancers and thermal barriers. We've seen good results from the use of these coatings, but the extra cost, when factored into the power this engine made, kept this entry from taking top honors.
Contributing tech editor Steve...
Contributing tech editor Steve Dulcich appropriately misuses a socket and extension for leverage to break the head bolts loose during teardown of the Speed-O-Motive entry for inspection. We were impressed with this engine; it was ready to run and needed little tuning to be competitive in our engine challenge.
Post dyno inspection of the...
Post dyno inspection of the Speed-O-Motive entry revealed nothing but quality parts, machining, and assembly techniques. Bore and stroke measured to confirm the engine's 496ci displacement, four inches shy of our 500ci limit.