2009 Amsoil Mopar Muscle Engine Challenge Schurbon Engine And Machine Mo-par City

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.

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.

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.

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.

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.