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2001-2016 Duramax SoCal Alternative Firing Order Drag Racing/Sled Pulling (9200AF)

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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.


Swapping a few pins in the wiring harness will insure the ECM sends the injector signal to the correct cylinder. Wiring diagrams and instructions are included with every purchase.

  • Requires .075 piston valve pockets.
  • Works well from 2500-5200 rpm.
  • Requires a high stall converter.
  • Valve Lash .012/.012
  • We recommend the use of LLY or later lifters. Do not use LB7 lifters.
  • 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.