Schurbon Engine and Machine/Mo-par City won this year's Amsoil/Mopar Muscle Engine Challen
If you're a regular reader or subscriber of Mopar Muscle, then there's no doubt you're familiar with our annual dyno competition. Each year we feature a different Mopar engine combination, giving engine builders from throughout the country the opportunity to demonstrate their skills during our contest. After being built, the engines are delivered to the Mopar Nationals where they are on display for the weekend, and then we take them to Comp Cam's dyno facility in Memphis to see how much power they make. This year, the Amsoil/Mopar Muscle Engine Challenge featured the low deck big-block, and all of the engines were required to run the same Edelbrock Performer RPM cylinder head. The price of the parts used to build each engine was factored into the combined peak horsepower and torque achieved on Comp's engine dyno, for a dollar per power factor used to determine the winner.
Because our rules factored used parts at fair market value this year instead of at new prices like past contests, the engine builders had to be creative, choosing economical parts where they could to save cost. All of our competitors used factory 400 blocks, and using a factory 440 crankshaft was an advantage as well, giving upwards of 451 cubic inches at a fraction of the cost of an aftermarket crank. Realizing that our rules favored inexpensively built engines, and that it would take a seemingly unachievable amount of power to cover the cost of an expensive motor, the top finishers in this year's contest utilized a variety of second-hand parts and economical new parts to complete their engines on a budget.
This year, Maquoketa, Iowa's Schurbon Engine and Machine teamed up with Mo-par City, building the least expensive engine in the contest, with sufficient power to capture the win. Placing a close second, and having the second most economically built engine, was Chenoweth Speed and Machine from Morton, Illinois. At nearly 600 horsepower each of these were stout big-blocks, running smoothly and pulling hard all the way to our contest limit of 7,000 rpm while on Comp's dyno. This month we'll go inside each of these engines and show you what parts and techniques were used to capture the top two spots in the 2009 Amsoil/Mopar Muscle Engine Challenge.
Schurbon Engine and Machine
Schurbon Engine and Machine has participated in several of our dyno competitions, always bringing a solid entry and placing second two years ago with their stroker small-block. Located in Iowa, engine builder Scott Schurbon says his shop will build anything, but loves the opportunity to build high performance Mopar engines. Interpreting the rules for this year's Challenge, Scott decided to build the cheapest engine possible that would still make enough power to be competitive, going for the win on cost. Combining efforts with Mo-par City, Schurbon Engine and Machine scored a win as their 451 inch 400 made more than 580 horsepower on Comp's dyno, running on Rockett Brand 93 octane unleaded fuel.
During his dyno session at Comp, engine builder Scott Schurbon had a trick up his sleeve. Since our rules allow parts changes so long as the parts are legal and the changes are accomplished during the timed dyno sessions, Scott made his qualifying pulls, then swapped his relatively expensive single-plane intake and Holley Dominator for a used Weiand tunnel-ram and a pair of second-hand 625 cfm Quadrajet carbs for a 30 plus gain in horsepower. While most people equate the Rochester Quadrajet with GM, Chrysler actually used these carburetors on their 318 4-barrel production vehicles for a short period, so we didn't give Scott too much grief about his choice of carbs.
Teaming up with Mo-par City, Schurbon Engine and Machine built a powerful 451 inch big blo
After his qualifying pulls, engine builder Scott Schurbon removed his single four-barrel,
Schurbon Engine and Machine utilized a variety of second hand parts to keep costs down, in
Since this is a normally aspirated street engine with moderate compression, Schurbon resiz
The 400 block was machined in-house to accommodate a factory forged 440 crankshaft and bal
Did we mention that Schurbon cut costs any way possible? Check out the single chain, stock
Rather than grinding the mains of the 440 crank to the smaller 400 dimension, Schurbon lin
As a foundation for their engine, Schurbon Engine and Machine started with a factory 400 block, performing all the necessary machine work in-house to accommodate the forged 440 crankshaft and Keith Black hypereutectic pistons. Mo-par City supplied a deep oil pan from an industrial crane, keeping oil away from the crank and eliminating the need for a windage tray, and assisted in the assembly of the bottom end. Factory connecting rods were deemed strong enough for this application, and far cheaper than aftermarket rods, so Schurbon fitted a set of standard 440 rods with ARP bolts and Clevite bearings. A stock, standard volume Melling oil pump was utilized to keep the engine lubricated, and the .600 plus lift Comp flat-tappet camshaft optimized power while costing much less than a roller cam and the associated hardware.
This year's rules required all the competitors to use Edelbrock's popular Performer RPM cylinder heads, and the engine builders were allowed to perform all the port work they liked. We also allowed epoxy modification to the ports, but no welding was allowed. Schurbon ported their heads in-house, raising the port to max wedge size and then filling the bottom of the intake port with epoxy to control port volume. The heads were then fitted with inexpensive stainless steel valves, Comp springs, and used retainers and locks. To actuate the valves, Schurbon used an ancient set of ductile iron 1.5 ratio adjustable rocker arms to save even more money on this inexpensive big-block. Though this engine showed up at the Mopar Nationals wearing an expensive new single-plane aluminum intake and Dominator, the induction was quickly changed to a used Weiand tunnel-ram and dual second-hand Quadrajets during the qualifying dyno session. This change both added power and saved money, resulting in a first place finish for Schurbon Engine and Machine.
All of this year's competitors used the same Edelbrock Performer RPM cylinder heads. Schur
Chenoweth Speed And Machine
Chenoweth Speed and Machine from Morton, Illinois, also calculated that it would take an inexpensively built low-deck to contend for the top positions in this year's Engine Challenge. The Chenoweth's are no strangers to Mopar engines, as their shop specializes in building Chrysler products of all types, from stock rebuilds to all-out race Hemis. Utilizing an array of second-hand parts combined with inexpensive new parts where necessary, engine builders Dale and Mike Chenoweth made this year's competition very close, coming within decimals of first place.
During their session on Comp's dyno, the Chenoweth's tuned their engine through a series of jet and timing changes, and then pulled the same trick as Schurbon, changing induction to a Weiand tunnel-ram and a pair of Carter AFB carburetors. Hoping for a gain in power, the induction swap was actually a disappointment, dropping power across the board. After a couple of quick tuning changes to the Carters, Mike and Dale determined they wouldn't be able to tune the tunnel-ram to the power of their single Dominator in the allotted time, so they switched back to the more expensive setup.
Ductile iron adjustable rocker arms were chosen to help control the cost of this engine. A
Starting with a factory 400 Chrysler block, the Chenoweth's treated the engine block to their "block in a bag" process, machining the block to precise specifications. Additionally, the mains were line-bored to the larger 440 size to fit a stock forged 440 crankshaft. Various second-hand parts were utilized including the forged I-beam connecting rods, oil pump, oil pan, windage tray, and even the Engle flat-tappet camshaft and Howard Cams oil-thru lifters. New Diamond forged pistons were utilized which added to the cost of the engine, and the rotating assembly was balanced in-house.
Choosing heads for this year's contest was easy as all of the engine builders were required by the rules to utilize the same Edelbrock Performer RPM castings. Chenoweth Speed and Machine ported their Edelbrock heads, performed a multi-angle valve job, then installed stainless-steel valves and new Chet Herbert valve springs. Although the Chenoweth's changed intakes during their dyno session, they changed back to their Edelbrock Victor 383 single-plane intake and Quick Fuel Technology prepped Holley Dominator when their dual-quads didn't make the expected power. Had the tunnel-ram worked, it would have saved enough cost to make this a much closer contest, though it would have been difficult to beat Schurbon's stout power score and low cost. We congratulate Chenoweth Speed and Machine on their very solid second place finish in the 2009 Amsoil/Mopar Muscle Engine Challenge.
|Chenoweth Speed and Machine||JD Engine and Machine|
|Mike Chenoweth||Jeff Dickey|
|Morton, IL, 61550||Columbia, MO, 65203|
|LaRoy Engines||Mid America Racing Engines|
|Jim LaRoy||David Bruns|
|Challis, ID 83226||Washington, IA 52353|
|Promax Performance||R.M. Competition|
|Ben Gorman||Randy Malik|
|Indianapolis, IN||Roseville, MI, 48066|
|Schurbon Engine and Machine|
|Maquoketa, IA, 52060|
The heads were ported to max-wedge dimensions, and then the bottom of the intake port was
To optimize power and save costs, Schurbon utilized a second-hand Weiand tunnel-ram with a
Though the Rochester carbs are inexpensive, they're also difficult to tune given time rest
Chenoweth Speed and Machine finished a close second this year as their 452 cubic inch big-
The dual-quad induction that the Chenoweth's bolted on dropped power significantly, causin
Like all of this year's competitors, the Chenoweth's started with a factory Chrysler 400 b
We're not sure how necessary they are, but the added gussets in the valley of this engine
By modifying a factory oil pan and pickup, Chenoweth Speed and Machine saved money and als
New Diamond forged pistons were matched to a set of reconditioned forged I-beam connecting
All of the competitors were required to use the same Edelbrock Performer RPM aluminum cyli
During their dyno sessions, the Chenoweth's swapped to a tunnel-ram intake but lost signif
....but eventually reinstalled the Edelbrock single-plane intake and Quick Fuel Dominator
The Chenoweth's noted that this engine wasn't making as much power as they thought it shou
To actuate the valves, the Chenoweth's used a second-hand set of Harland Sharp aluminum ro
Running Rockett Brand 93 octane pump gas, Dale and Mike Chenoweth tuned their economically