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Yunick Motorsports
271 Commercial Drive
Woodbine, GA 31569
(912) 617-0101

High Performance Engines

In 1966, General Motors (GM) took its famous 396ci gas burning, big block and increased its bore to 4.25 inches. With that one simple machining process, GM gave birth to the famous 427ci Rat motor and Chevrolet carved its notch into American muscle car history forever.  Since the 6.6L Duramax became a viable performance engine, it was only a matter of time before some horsepower junky took the 402ci diesel and ripped out its guts to stuff it full of forged, billet and coated power parts in search of more cubic inches. We are offering new Diesels; 427ci Duramax stroker kit that increases the size of a Duramax engine from 6.6L to 7.1L (427ci) by fitting the engine with an inch longer stroke. That’s right, the big block 427 is back ~ only now it is a diesel!

How Much Power Can The 7.1L Stroker Kit Add?

A 7.1L Duramax can be tuned to make 750 hp to 900 hp and 1,400 to 1600 lb-ft of torque.

We offer three different levels of engine rebuilds:

Step 1: Budgets / Vortec (500HP - 600 HP)

Step 2: LS3 & LS7 (700HP - 800 HP)

Step 3: Diesels (700HP - 900HP)

Duramax Engines


LS3 427 CID Engines


Cummins Engines



Allison 1000, 2000, 2400 Series

Chevrolet and GMC Trucks with Duramax Diesel and Gas Engines

  • Valve bodies are fully modified and calibrated to provide quick, positive shifts
  • Modified "A" and "B" trim solenoids are installed to further improve shift quality
  • Revised C-2 and C-3 clutch hydraulic circuitry virtually eliminates codes/limp mode under extreme load conditions
  • Additional clutches are installed to increase torque capacity
  • High Energy friction material is installed in all clutch packs.
  • Hydraulically re-engineered to maintain higher line pressure under converter lock-up operation
  • Pump is modified to provide increased pressure and volume
  • IPT's Allison Transmissions are mechanically and hydraulically bulletproof and represent the most robust package of modifications available anywhere. The need for aftermarket electronic controls are eliminated in all but the most extreme power applications.