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SoCal Diesel Duramax - Max Power!

CNC-Ported Duramax heads for street or race

Jason Sands
Aug 31, 2007
Photographers: David Kennedy, Jason Sands
Photo 2/14   |   socal Diesel Duramax scrap Castings
Anyone who has been on the search for more power always knows there's a proverbial "next step." From the factory, engines are compromised by emissions, durability, noise levels, vibration levels, and a thousand other things. The aftermarket has come through with many products that can conquer these restrictions set in by the factory.
Many programmers are out there-some with 150-plus horsepower at the push of a few buttons. Still not enough? Compound (or twin) turbo setups are available for those who want to push their trucks even further, along with modified injection pumps to fuel them. If your stock tranny and rods aren't junk by now, they will be. And then there's always nitrous. Still, there are those out there who are looking for more, and for those people SoCal Diesel is offering a line of CNC-ported Duramax cylinder heads.
When it comes to engines, more airflow usually equals more power (as long as everything else is matched well). Eventually, you can only force so much fuel and boost through an engine before the cylinder heads become a restriction.
With a stock turbo, this isn't an issue, but as the boost pressure rises toward the stratosphere, the stock heads will only flow so much. Porting the cylinder heads can dramatically increase the airflow that will go into the combustion chamber, and when properly matched with a turbo and enough fuel, it will generate more power. With ported heads, boost pressure can actually go down because there's a larger total space for the fixed amount of air a turbocharger can put out. For this reason, Guy Tripp, president of SoCal Diesel, will only recommend his Stage II heads for those who have already modified their trucks with a turbo and/or fueling upgrade.
Right now, there are two offerings from SoCal Diesel, a Stage I port and a Stage II. The Stage I is for high-mileage trucks that need rebuilt heads or for those wanting a little better throttle response and performance from their engine.
Stage I includes a complete rebuild with guides, custom springs, retainers, a five-angle valve job, and CNC porting of the radius of the intake inlet and valve bowls. Stage II is for those who are interested in sled pulling or drag racing and gains an impressive 60 cfm on the intake and exhaust while still maintaining driveability. It has all the features of Stage I, plus oversized intake and exhaust valves made out of stainless steel and Inconel, respectively, as well as full CNC porting of the intake and exhaust ports. To take advantage of this increase in flow, custom camshafts for towing, drag racing, and sled pulling are also offered. Stage II is the current "Race" offering, and (as of press time) a Duramax with Stage II heads made just over 1,000 rear-wheel horsepower and almost 2,000 lb-ft of torque on #2 Diesel only.
For some people, more is never enough, and with 24 years of experience in the cylinder-head industry, Tripp is always looking ahead. A Stage III port (which will push the envelope even farther) is in the works, and a rev kit is also being developed for the camshaft. As these engines are flowing more air, pushing more boost, and turning more rpm, the valvetrain is giving up. Guy hopes to be able to cure this with the rev kit, which will allow a bigger cam with more spring pressure to be run without increasing the valvetrain's mass. So stay tuned for more, but for now, we'll take a look at what goes into the porting of a Duramax cylinder head.


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