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Arrington Performance    

Welcome to the ShopHEMI.com Arrington Engines Building Tour

When a HEMI engine or a 2011 Dodge Challenger arrives in our shop, it gets the royal tratment. Check out below to see the steps involved in a typical turn-key performance HEMI build.
Shipping and Receiving

Drop it off

Our climate controlled shop is waiting for your HEMI. Your car will be locked in our installation facility and kept comfortable and safe away from the elements and prying fingers until your build is complete. Trust your car to our hands and let us transform it to a modern muscle car fit for the street or the strip.


Look too clean? We like it that way. After your HEMI engine is pulled from your vehicle, it is moved to the disassembly bay for teardown and initial inspection. The Hemi undergoes its initial inspection for damage to pistons, heads, crank journals, etc. This evaluation helps us determine the quality of a core and it provides feedback to our engineers allowing us to improve quality and durability guaranteeing the best HEMI performance parts.
Cleaning Stations


Environmentally friendly parts washers clean all engine parts from block to bolts. Removing the oil and buildup from the cylinder walls and cooling passages in your engine allows us to do final testing on cleaner than new parts before they are approved for a rebuild.
Engine Build and Inspection bays

Inspection and build stations - We’ll Be coming back here...

Final inspections such as magnaflux testing, sonic checking, and verification of critical measurements such as deck height, bore, cylinder wall thickness, and more are completed to the tenths of a thousandth of an inch. To properly assess the core quality and set up the CNC machines allows us to provide precise cubic inch displacements, volumetric efficiency and calculate precise swept volume. It is critical that these measurements meet minimum tolerances before and after the block and cylinder heads are machined.
Hand De-burring and Grinding Booth

Cylinder block de-burring and grinding

We keep this in a separate area of the building under negative pressure to decrease the chances of fine particulates produced during the rough processes from contaminating the engine installation and assembly areas. Hand de-burring and grinding decreases the sharp edges and begins the smoothing process of imperfections in HEMI engine block surfaces. If not smoothed these could develop into cracks under the prolonged strains of high horsepower and torque.
Boring Station (separate building)

CNC Cylinder boring

We mean precise. The cylinder bore is accurate down to the tenth of a thousandth of an inch. (.0001”) Cylindricity and concentricity are keys to high horsepower HEMI engines. If your cylinders are out of round or alignment is off, when force is applied to the piston through combustion or boost you set yourself up for failure. This CNC procedure ensures alignment of cylinders relative to the mainline, and aligns cylinder bore centers with companion cylinders.
Final Hone.

Cylinder Finishing or Final Hone

All cylinder finishes aren’t produced in the same manner. From boosted applications with tons of force requiring cylinder sealing, medium finishes for NA HEMI engines, and diamond mirror finishes on a NASCAR Sprint Cup series all have different requirements. Every cylinder has to be finished properly to perform at its peak, without creating frictional loss. Different roughness and RA scales are used for precise cylinder finishes to ensure quality sealing and combustion. This is not a step to skip.
CNC Crank Balancing


Balancing only takes one machine. Adding or removing material is what produces a balanced final product. That takes another 2 machines. We use CNC Lathes and 3 axis CNC drill presses to remove or add material to the crank then return to the balancer for evaluation. After that we polish the crank to remove any surfaces that can trap oil or fine particles. So in total our balanced HEMI crankshaft takes 4 machines to produce. Sound complicated? We do all this to the gram and the .0001” so that our crankshafts produce no vibrations and are perfectly balanced. Every counterweight, rod journal, and main journal is machined to the exact size and weight proper for your application. Ask other engine builders how many machines they use...
Newen EPOC Valve Seats.

Valve Seats

When we are asked how many angles our valve job is we say none. Our Newen Epoc CNC valve job is a single point operation. The angles and steps are so small that they are reduced to a near true radius. From there the heads are taken to a 5 axis CNC mill where ports specifically designed to produce maximum air velocity from intake and exhaust ports are machined. Finally these heads are taken to assembly where strengthened springs, keepers, and retainers are installed in the casting. Why accept the industry standard stock hardware, 3 point valve job, and a fluff and buff port when looking for maximum performance?
State of the Art Machine Shop

The Machine Shop

Available for a custom job for hire or to assist our techs with a modification needed for proper installation of your hemi engine, our complete machine shop is ready to work. You name it; we can do it down to the smallest of details or the roughest of cuts. 4 -5 full axis CNC machines and a host of other smaller machines, lathes, and measurement tools are precise down to measurements that the human eye will never see and can be utilized for one off tooling or volume production.
5 Axis CNC Machining

Why 5 Axis CNC?

Precision 5 axis CNC machines are capable of ultra fine accuracy, and guarantee that your performance part or custom mount is machined to perform. These machines are liquid cooled to reduce fatigue caused by excessive heating of sensitive materials during the machining process. Automatic tool selection and machining ensures quality and precise locations, sizes, and thickness of the material being machined.
Final Wash

Clean It Again

After all machining and preparation is complete, all parts and HEMI engine blocks return to the washers. A 200 degree engine block washer opens pores in cylinders to make sure not even the smallest of particles remain that can stop up oil passages in our engines. Cylinder cleanliness is important for final assembly and prolonged intense operation. Final white towel cleaning by hand ensures proper cylinder sealing and ensures no dirt or grime will cause piston rings or mechanical parts to fail.

And we’re back to inspection and assembly.

After a final check on tolerances your HEMI is assembled by an expert engine builder. Torque is applied every bolt. Piston to valve clearance is double checked. Cam timing and bearing clearances are verified. Finally front dress, accessories, and belt tension and pulley alignment is adjusted.
Final Installation.

From an assembly bay to your high horsepower street car

You can ensure our NASCAR proven power, technology and research and development will all be included in YOUR aftermarket package. All processes take place in our climate controlled and ultra clean shop to ensure accuracy and detail.
Dyno and Tuning

Dyno and Tuning

At the end of the install, your build is dyno tuned on a SuperFlow certified chassis dyno. Not your standard roll away dyno, this eddy current precision dyno has separate climate controls and fire suppressant systems. When we tune your HEMI and your ride leaves our shop, you won’t just happy - you’ll be impressed.
Shipping and Receiving

And then it’s out the door

shopHEMI is determined to make loyal customers not just one time quick dollars. That is why we know our or products and know customers names, stories and faces. Not only are we committed to extreme horsepower builds for customers, we are also enthusiasts!
Contact Customer Service for immediate information on customer-related questions.