2005 Hemi Engine Challenge - Domesticated Elephants

Those who have been following our Hemi engine challenge know that the big horsepower and torque numbers put up by our contestants were certainly impressive, but there was more to our contest than raw power. Cost was factored into the power and torque the engines made, so the competitors had to budget wisely, spending money where it made the most economical sense. These engines also had to demonstrate the ability to make power on 93-octane fuel and were subjected to multiple dyno pulls at a relatively slow acceleration rate to test their longevity and streetability. What is streetability? To us, it is defined by many factors, such as being able to idle in traffic without overheating, running strong on gas that's available at the local station, and longevity that will allow many years of reliable cruising.

This month, we'll go inside the Indy Cylinder Head and Mid America Racing entrants to see what combination of parts makes these engines true street performers.

Indy Cylinder Head Indianapolis, IN
Indianapolis, Indiana, home of the Indy 500 and the NHRA U.S. Nationals, has long held the title as the racing capitol of the world, so it comes as no surprise that one of the leaders in aftermarket support for Mopar engines grew from a shop in Indianapolis. Indy Cylinder Head began supporting Chrysler enthusiasts with quality aftermarket products more than thirty years ago and hasn't looked back since. Realizing that big-block Chrysler heads would always be limited by their relatively short valves and subsequent lack of port volume, Indy manufactured quality heads using valves 1/2-inch longer than stock, and dramatic horsepower gains were achieved. Since their early days, Indy has branched out and is now manufacturing quality products for nearly anything Mopar, including their Legend line of Hemi cylinder heads, intake manifolds, and blocks. nearly all of the competitors in this year's challenge utilized some type of part manufactured by Indy Cylinder Head in their engines.

With years of research and development and countless hours at the track and on the dyno, the crew from Indy Cylinder Head was expected to perform very well at our challenge, so their fifth place finish had us scratching our heads. The engine made good power and torque, but based on our experience with Indy it was definitely down on power. Upon the tear-down of their motor, the cause of their problem was evident. Rather than bring one of their established combinations to our competition, Indy chose to use our contest for some research and development. Experimenting with a new billet, flat-tappet camshaft in their motor caused several of the cam's lobes to wear excessively, almost to the point of being round, which severely limited the output of this engine. Had they not been using their entry for research, their numbers certainly would have been better, but trying new technology is the way to stay ahead of the competition, and for that we compliment Indy Cylinder Head.

Indy Cylinder Head is well known for making reliable power so we were particularly interested in what goodies were stuffed into their Mopar Performance Hemi block. What we found inside was a different approach than was used by the other competitors. Indy had chosen to build cubic inches by the utilization of a relatively long-stroke, small-bore combination, which theoretically should make killer torque. After performing all the block machining in-house, Indy installed a Callies 4340 411/42-inch stroke crankshaft combined with the block's bore of 4.2 inches to net their 499 ci. Manley 6.86-inch, center-to-center-length, H-beam steel connecting rods were chosen because of their reputation for strength, and the use of Aries small dome pistons achieved a pump gas friendly compression ratio of eleven-to-one. No special internal coatings were utilized in this combination as Indy claims a limited benefit at the rpm range of the competition. To keep everything well oiled, Indy utilized Milodon's 7-quart pan along with their 11/42-inch internal pickup and high-volume pump. A Milodon windage tray was also installed to keep power robbing oil off the crankshaft. To keep costs down, a stock 440 balancer, timing cover, and pulleys were used to finish off this stout short-block.

We were interested in which of their many available cylinder heads Indy would use to top off this motor. Knowing that cost as well as power would be factored for the competition, the guys at Indy chose their CNC 285 aluminum units (PN 426-1) for this engine. These heads come fully CNC ported and flow an impressive 440 cubic feet per minute out of the box. Filled with stainless steel 2.25-inch intake and 1.94-inch exhaust valves held in place by Comp cam's 927-16 valvesprings with 10-degree titanium retainers, these heads certainly had the potential to post big power numbers. To actuate the valves Indy used their own rocker kit (PN 426-27) with 1.6-ratio intake and 1.55-ratio exhaust rocker arms. A fully ported and polished 426-2 intake manifold utilizing a 4150-size flange was matched with a 4500-flanged Barry Grant 1090 King Demon carburetor by the use of an adapter that was ported with the intake. We have experimented with this setup ourselves and have seen gains of 12 to 15 hp over 4500-flanged intake manifolds. When the time came to select a camshaft for this engine, the Indy crew had a choice of installing one of their proven custom grinds or to experiment with new technology. Always attempting to stay on the cutting edge and ahead of the competition, Indy chose to experiment with a flat-tappet camshaft that was custom ground from a billet core commonly used for roller camshafts. Specifications on the custom grind were .624-intake and .617-exhaust lift and 255- and 259-degrees duration at .050 inch lift. In theory this cam would give much more precise valve timing, but, unfortunately for Indy, it wasn't compatible with the steel lifters and caused several lobes to be damaged during the dyno pulls, severely limiting the power of this engine. Even so, the more than 649 hp and over 600 lb-ft of torque are a clear indication of this combination's potential had it not been for the damaged camshaft.

While we're sure the guys at Indy expected more from their entry, we have to congratulate them for their willingness to experiment with new technology. It is no wonder that Indy Cylinder Head is the leader in the Mopar aftermarket. This is a solid combination of parts that offers not only power but longevity. We encourage you to call Indy about your project as they have combinations catering to any budget or power level.

David Bruns of Mid America Racing Engines in Washington, Iowa, definitely knows the ins and outs of going fast. Even before starting his machine shop David and his family were avid drag racers, building their own powerful engines and always ready to help their fellow racers. This philosophy has carried over to his business where David is happy to help performance enthusiasts achieve their power goals in the most economical way possible. Whether a slightly warmed-over street engine or a full-on big-inch racing mill, Mid America delivers honest combinations that exceed their customers' expectations. When it came to choosing parts for his entry in our engine challenge, David decided to build an honest street engine that would not only make respectable power, but would have the endurance to last for years of enjoyment in a pavement pounding street car. While our contest was factored on peak power, and the Mid America entry made more than 665 peak horsepower, this engine had very broad torque and power curves and made well over 500 lb-ft of torque at a leisurely 3,000 rpm. Had our contest been based on average torque and horsepower over the rpm range of the contest, this entry would have certainly placed higher in our contest.

After receiving his Mopar Performance Siamese-bore Hemi block, it was fully checked and stress relieved before the main journals were line honed and the cylinders were bored to 4.375 inches. With a compression ratio of approximately ten-to-one, this engine was probably the most honest street engine in our contest. Inside the block, Mid America utilized an Eagle crankshaft with a 4.150 stroke. The crankshaft was stress relieved, the oil holes were radiused, and it was internally balanced before being installed in the engine. Tough Manley connecting rods were used for their endurance and JE pistons were employed to keep compression at a pump-gas friendly ten-to-one. The only trick employed by Mid America was the application of a friction-reducing coating to the piston skirts. Oiling duties were handled by a reliable Moroso 7-quart oil pan and pickup combined with a Melling high-volume oil pump. To dampen harmonics, a Professional Products SFI-approved balancer was utilized. A Melling double-roller timing chain and gears kept the camshaft in synch with the crank in this solid short-block.

Topping his stout short-block, David chose to use Indy's CNC ported cylinder heads (PN 426-1RA). The thermal efficiency of a steel cylinder head may have made a pony or two more, but David chose to stay with his theme of a realistic street motor, stating that the weight savings of the aluminum heads may not reflect a gain on the dyno, but would certainly be an advantage when the engine is installed in a car. Indy stainless steel valves were matched with Isky gold valvesprings and Crane 10-degree retainers and locks to keep everything solidly in place. An Indy Cylinder Head 426-3 intake manifold with a 4500 flange was match ported to the cylinder heads and topped with a Holley Dominator carburetor to handle the air/fuel mixing. An Isky solid lifter flat-tappet camshaft was selected to actuate the valvetrain. David was somewhat tight lipped about the specifics of this camshaft; all he would tell us is that lift is in the .600- to .650-inch range and duration at .050-inch lift was in the 250-degree range. What we do know is this camshaft provided very broad torque and power curves adding to the true streetability of this combination. The engine was fastened together with ARP hardware and sealed with Victor-Reinz gaskets.

We must say we were impressed with this entry in our contest. It took nerve to build a relatively conservative street motor for our contest, and we congratulate Mid America Racing engines for their strong showing. Of all the engines in our contest, this one sounded happiest on the dyno without so much as a hint of detonation. This engine would have run just fine on 87-octane fuel and is a durable and powerful combination. Powerful engines combined with professional business practices and genuinely good people make Mid America Racing Engines the perfect choice for your next build.

That's All There Is There Ain't No More
The '05 Mopar Muscle Engine Challenge is over. We had some of the best engine builders in the country build a 500-inch Hemi, run it on the dyno, and then we told you what's inside. Keep in mind, this Challenge was to allow each of these engine builders the opportunity to showcase their skills, and build engines that could be repeated for anyone that called the shop. We had a lot of horsepower, we had a lot of torque, and we even had engines that looked like restored elephants. So remember, if you are looking to have a Hemi built, keep these shops in mind because they have proven themselves as great engine builders.