Since the rules prohibited...
Since the rules prohibited welding or epoxy modifying their heads, Indy pressed in brass sleeves instead, freeing up more port volume and flow potential. This interpretation of the rules likely gave them just enough power to win this year's contest.
Using lighter valves from...
Using lighter valves from the new Chrysler Hemi meant the combustion chambers had to be recessed into the cylinder head casting. Indy used this opportunity to CNC machine the combustion chamber to their popular 572-13 combustion chamber dimensions.
Port shape was optimized in-house...
Port shape was optimized in-house by good old-fashioned manual porting with the help of a flow bench. This engine made great power, even topping a couple of aluminum-headed motors.
Indy used several tricks to...
Indy used several tricks to find incremental horsepower gains, including under-driving the water pump with a relatively small crank pulley.
Multi-layer steel head gaskets...
Multi-layer steel head gaskets were used to keep the combustion chambers sealed. We've found these gaskets seal as well as copper gaskets with O-ringed heads.
Indy used their own rocker...
Indy used their own rocker arms with Comp "beehive" valvesprings to keep the valve gear under control at rpm. The stud girdle was manufactured in-house as well and valve guides were used as spacers.
To optimize power from this potent small-block, the Indy crew used a Comp solid flat-tappet camshaft and Indy rocker arms to actuate the valve gear. Comp "beehive" springs kept the valves under control at rpm, and an MSD distributor fired the cylinders. An Indy single-plane aluminum intake matched with a Demon 850 four-barrel carburetor took care of induction, and Schoenfeld headers expended the burnt gasses. To save costs, factory valve covers were used, along with a factory timing cover and oil pan. Overall, this engine made great power from economical hardware, and we really enjoyed seeing the crew from Indy optimize an engine that didn't wear Indy heads. We congratulate Indy Cylinder Head for winning the '07 Amsoil/Mopar Muscle engine challenge.
|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|
Narrowly missing a first place...
Narrowly missing a first place finish, the Schurbon Engine and Machine entry made nearly 500 hp and an incredible 460 lb-ft of torque to finish second in our Engine Challenge.
Schurbon Engine And Machine
When we spoke with Scott Schurbon of Schurbon Engine and Machine at the beginning of our contest, he stated he would bring a strong engine, but wouldn't sacrifice reliability for power. Scott said his engine would be one just like he would sell his customers, and he wouldn't use cheap parts simply to place better in the contest. During the dyno portion of the challenge, it was apparent this engine was not only a strong performer, but also had the potential to place very well in the contest. Scott and his crew effectively tuned their entry to more power on each pull, even swapping to a smaller, less expensive carburetor without losing power. This engine sounded strong and smooth, and performed flawlessly allowing Scott plenty of time to tune his engine to nearly 500 hp and a stump-pulling 460 lb-ft of torque!
Everyone agreed that the Schurbon entry looked great wearing its Plum Crazy purple paint job, and it performed as good as it looked once on Comp's dyno. Inside their factory 360 block, Scott utilized an Eagle cast-crankshaft, RPM connecting rods, and Probe pistons to net a displacement of 410 ci. A standard volume Melling oil pump was matched with a Moroso oil pan, but we noticed the absence of a windage tray in this engine. When asked why, he stated the windage tray would have to be modified to work properly, and he simply ran out of time before the engine had to be delivered to the Mopar Nationals so he welded baffles into his oil pan instead. Even with no windage tray, this engine performed flawlessly and had no oil-related issues while making its dyno pulls.
To top his short-block, Scott used cast-iron Magnum cylinder heads that were ported in-house for optimal flow. Since this is a street engine, Scott decided not to overdo it when it came to port volume and camshaft. He says he likely left a little on the table as a larger cam would have made more power, but at 460 lb-ft of torque, this engine would perform great in a street car. Inside his cylinder heads, Scott used extreme-duty, stainless steel valves and Comp springs. A Comp solid flat-tappet camshaft actuated the valve gear through Scorpion roller rocker arms. Scott manufactured a stud girdle for the rockers in-house and had no problems spinning his engine to the required 7,000 rpm. A factory Mopar timing cover and Mopar aluminum valve covers were used to keep costs down.
The Schurbon entry performed...
The Schurbon entry performed flawlessly, allowing the crew to try multiple tuning techniques, including valve lash adjustments, carb spacers, and even a carb change.
During his qualifying pulls,...
During his qualifying pulls, engine builder Scott Schurbon sensed something just wasn't right. Quickly finding his engine wasn't getting wide-open-throttle, dyno operator Rich Smith corrected the problem by adjusting the dyno throttle.
Probe pistons and RPM connecting...
Probe pistons and RPM connecting rods, along with an Eagle crankshaft, formed the foundation of this powerful small-block.