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2001-2016 Duramax SoCal Alternative Firing Order Camshaft #3388AF

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  • Overview
  • Features
  • Fits
  • Notes

Extend the life of your crankshaft by changing the firing order of your engine.


The OEM firing order ends with cylinder 3 and begins with cylinders 1 and 2. The result is a 3-1-2 hit to the crankshaft. Duramax cranks have a tendency to break right behind the first rod throw at the intersection of the second main journal, right where the 3-1-2 hit would stress the crankshaft the most. Coincidence? We think not.


After carefully researching the different firing orders available to a V-8 engine, SoCal Diesel was the first to implement this "Alternative Firing Order" camshaft for the Duramax engine. In moving cylinders 3, 1 and 2 away from each other, we have significantly extended the abuse the crankshaft can withstand.

  • Does not require any piston valve pockets.
  • Works well from idle past 3800 rpm.
  • Valve Lash .012/.012
  • The camshaft is an integral part of your engines breathing characteristics. 
  • The camshaft lobe profiles need to be carefully matched to the rest of the engine components in order to achieve maximum performance for any given application. 
  • We have designed profiles to meet many different applications that include dedicated Drag Racing and Sled Pulling. 

GM Duramax

2001 - 2016

Valve Adjustment Procedure


1.   Rotate the engine and adjust one cylinder at a time.

2.   When the exhaust valves just begin to open, adjust the intake.

3.   When the intake valves are just past maximum lift, adjust the exhaust.


Most orders are shipped 1-2 weekdays after an order is placed, depending on availability.


If you have any questions about this product/tune, give us a call or submit a contact form. We will get back to you as soon as possible.