Mopar Stroker Small Block - The 2007 AMSOIL/Mopar Muscle Engine Challenge
A Look Inside Two Of The Most Powerful Challenge Engines
From the May, 2008 issue of Mopar Muscle
By Dave Young
Photography by Dave Young, Randy Bolig
It takes horsepower to be competitive in our Engine Challenge, and the two small-blocks we're featuring this month made plenty of it. In fact, the R.M. Competition entry was just shy of winning, placing a very close Third in our tightest competition to date. The Mid America Racing Engines entry also impressed us by making the most combined power of any engine in this year's Engine Challenge, screaming to more than 560 pump-gas-friendly horsepower and nearly 500 lb-ft of torque. Equally as important as the power these engines produced was the budget the builders adhered to. Since the cost of each engine is factored into the combined power, engine builders had to carefully spend money where it benefited their combination the most.
This month, we'll go inside the Third Place entry of R.M. Competition and the Fourth Place entry of Mid America Racing Engines, detailing the parts and techniques that made each engine competitive.
Placing Third and Fourth,...
Placing Third and Fourth, respectively, in the '07 Engine Challenge, R.M. Competition and Mid America Racing Engines brought powerful small-blocks to our contest.
This month we'll look inside...
This month we'll look inside these engines to see what tricks these builders used to place well.
|Diamondback Engines||Indy Cylinder Head|
|7723 FM 723||8621 Southeastern Ave.|
|Richmond, TX 77469||Indianapolis, IN 46239|
|Mid America Racing Engines||MRL Performance|
|1945 W. 18th St.||4651 Culley Ln.|
|Washington, IA 52353||Jackson, MI 49201|
|Muscle Motors||R.M. Competition|
|2085 Glenn St.||28648 Maple|
|Lansing, MI 48906||Roseville, MI 48066|
|Schurbon Engine and Machine||Speed-O-Motive|
|203 S. Clark St.||131 W. Lang Ave.|
|Maquoketa, IA 52060||West Covina, CA 91790|
Engine builder Randy Malik came very close to winning this year's Engine Challenge. Placing a close Third, this engine was mere decimals away from the Second and First Place entries in ouandy placed so well was his careful selection of budget parts, and making more than 500 hp on the dyno certainly didn't hurt. This engine was a well thought-out combination of powerful parts and was built on a tight budget since cost matters as much as power in our contest.
Starting with a production Chrysler 360 core motor, Randy performed the necessary machine work in-house. The factory block was bored to accommodate Keith Black hypereutectic cast pistons and Perfect Circle piston rings. A Scat stroker crank was matched with factory connecting rods to net a displacement of 406 ci. A production 360 oil pan was also utilized to keep costs down, and a custom windage tray was fabricated in-house. Melling was the manufacturer of choice for the oil pump, timing set, and lifters, and Federal Mogul and Durabond bearings were used in this engine. Knowing the importance of camshaft selection, Randy chose a large Lunati flat-tappet unit to work with the Weiand tunnel-ram intake.
To top his stout bottom-end, Randy chose Mopar Magnum cylinder heads from Engine Quest. Magnum heads adorned the top three finishers in this year's contest and make great power for the money. REV engine valves were utilized along with valvesprings matched to the Lunati bump stick. Harland Sharp roller rocker arms with a 1.7 ratio were used on the intake side, while Crane 1.6 ratio rockers were chosen for the exhaust side. A composition head gasket was used to seal the combustion chambers, and Randy claims compression ended up right at 12.2:1, pushing the limit for pump gas. While the Weiand tunnel-ram intake isn't really what Randy would recommend for a street car, it worked great on the dyno where peak horsepower and torque were used to help determine the winner. While no special coatings per se were used on this engine, he did paint the bottom of the intake with epoxy paint to help insulate the intake from the hot oil. A matching pair of Edelbrock carburetors topped the engine, and an air cleaner was fabricated from wood, again to keep cost down.
Randy Malik of R.M. Competition...
Randy Malik of R.M. Competition tuned his Magnum-headed stroker small-block to more than 500 hp on pump gas, clinching Third Place.
As the only engine to utilize...
As the only engine to utilize dual four-barrel induction, the R.M. Competition entry was budget built and made impressive horsepower with cast-iron Magnum cylinder heads.
Tunnel-ram induction combined...
Tunnel-ram induction combined with a pair of Edelbrock four-barrels may not be the most streetable combination, but this engine made great power on the dyno.
Dual-quad induction kept Randy...
Dual-quad induction kept Randy from making any jet changes on the dyno, but he still tuned his engine to impressive power with timing and spark plug changes.
Our rules stated the engines...
Our rules stated the engines would be filled with Amsoil to the pan's capacity, but didn't say anything about the oil filter. Randy picked this 11/2 quart unit to keep more oil out of the crankcase, reducing windage and, thereby, improving power.
Inside his 360 block, Randy...
Inside his 360 block, Randy used a Scat crank with stock rods and Keith Black cast pistons. Note the fabricated windage tray necessary for the additional stroke.
Randy chose a Lunati solid...
Randy chose a Lunati solid flat-tappet camshaft to work with his tunnel-ram induction, but no modifications were performed to keep oil away from the cam tunnel.
Magnum cylinder heads offer...
Magnum cylinder heads offer a great combustion chamber design, large valves, and good port volume and configuration. They're reasonably priced as well, so it's no wonder the top three engines all used Magnum heads.
Stock rods and cast pistons...
Stock rods and cast pistons might not work in a serious race application, but for this dyno challenge, they survived multiple pulls and kept costs down.
A combination of Harland Sharp...
A combination of Harland Sharp and Crane rocker arms kept the valvetrain in check, allowing Randy to tune his small-block to more than 500 hp and a Third Place showing in this year's Engine Challenge.
Cylinder heads were ported...
Cylinder heads were ported in-house to optimize flow, and these Magnum heads have the LA-style intake bolt pattern, allowing less expensive and more readily available intake manifolds to be used.
While no exotic coatings were...
While no exotic coatings were used, the bottom of the intake was painted with epoxy paint to keep heat away from the intake charge.
Mid America Racing Engines
Engine builder David Bruns of Mid America Racing Engines has brought competitive engines to all our competitions to date. The Hemi he brought to the first Challenge was a solid street engine with very broad torque and power curves, and last year's big-block impressed us with awesome power and torque, winning the '06 Engine Challenge. This year David brought yet another good engine to the contest, impressing everyone in attendance by making nearly 570 hp and 490 lb-ft of torque for a contest-leading combined score. While the expense of aluminum cylinder heads and a roller cam kept him from another win, we were still impressed with the power and reliability of this engine, earning Mid America Racing Engines a Fourth Place finish.
David Bruns of Mid America...
David Bruns of Mid America Racing Engines won last year's contest and though placing Fourth overall this year, earned the honor of making the most horsepower in this year's Challenge.
In 2006, engine builder David...
In 2006, engine builder David Bruns won our competition. This year his small-block made more power than any of the competitors.
Indy aluminum cylinder heads,...
Indy aluminum cylinder heads, a high-volume single-plane intake, and a stack of carb spacers helped engine builder David Bruns attain contest-leading power in this year's Engine Challenge.
Like most competitors this year, David used a stock 360 core block as the foundation for his build. The block was machined in-house for Probe forged pistons with PBM piston rings and an Eagle 4-inch stroke crankshaft. Scat connecting rods were utilized for their durability; the compression ratio of this 410ci small-block was 11.7:1. To handle oiling, David chose a Moroso oil pan, which he modified by adding oil control baffles, combined with a Milodon windage tray and Clevite oil pump. Oil from the top end was routed to the pan via the back of the block and away from the rotating assembly by metal plates under the camshaft tunnel. King rod and main bearings kept everything spinning freely, and Clevite cam bearings held the Cam Motion solid roller camshaft in place. A PBM timing set was used to spin the cam and enclosed by a stock timing cover.
Going for big power numbers meant utilizing aftermarket cylinder heads, and engine builder David Bruns chose Indy 360 H1-1 units to top his engine. These heads were machined in-house for stainless steel 2.125-inch intake and 1.65-inch exhaust valves and PBM roller valvesprings. David also ported the cylinder heads himself, reshaping the exhaust ports to mimic the proven profile and volume of Mopar W-2 cylinder heads. To actuate the valves, 1.6-ratio Indy roller rocker arms were used along with 3/8 -inch-diameter hardened pushrods. Knowing this combination would like an intake with big runners and a high plenum volume, David chose the Indy 360-14-3R aluminum single plane intake for induction duties. Double carb spacers beneath the Holley 1,000-cfm 4150 series carb provided additional intake volume, and additional power for this combination. Ignition was handled by an MSD distributor.
Inside his 360 block, engine...
Inside his 360 block, engine builder David Bruns utilized an Eagle crank, Scat rods, Probe pistons, and a Cam Motion solid roller camshaft.
A Milodon windage tray along...
A Milodon windage tray along with a Moroso pan with added baffles helped keep power-robbing crankcase windage to a minimum.
Looking closely, you can see...
Looking closely, you can see one of the metal plates epoxied in place under the camshaft tunnel in the block. These plates direct returning oil to the back of the block and into the pan without soaking the rotating assembly, also helping reduce crankcase windage.
Scat I-beam connecting rods...
Scat I-beam connecting rods are hard to beat for the price, and Probe flat-top pistons helped this engine achieve contest-leading power.
Using Indy heads with modified...
Using Indy heads with modified ports necessitated the use of header adapters on the Mid America entry. Schoenfeld headers expelled the spent gasses.
The Indy heads used on this...
The Indy heads used on this engine were ported in-house, and the exhaust ports were modified to the tried and true W-2 port dimensions.
Since Indy heads require a...
Since Indy heads require a different rocker arm offset, David utilized Indy's 1.6-ratio aluminum roller rocker arms.
Though placing Fourth overall,...
Though placing Fourth overall, making the most power in the contest is certainly a win of sorts for Mid America Racing Engines. We congratulate David Bruns on his strong performance in this year's Engine Challenge.
With an excellent combustion...
With an excellent combustion chamber design, big valves, and big ports, aluminum Indy cylinder heads were one of the keys to Mid America's contest-leading power numbers.