CAMSHAFT – The AFM engines have a special camshaft.  The mechanism required for the AFM lifters to turn on/off requires the individual lobes of the cam with AFM lifters riding on them to be DIFFERENT than adjacent lobes with standard lifters.  You MUST replace the camshaft if you are going to replace the AFM lifters with standard lifters.  Failure to do so will result in 4 cylinders that are about 25 lbs low on compression. This WILL cause misfires at idle.  (Learned this the hard way, take my word, CHANGE THE CAMSHAFT)

2014+ Gen 5 Engine Family, including 5.3L L83, 6.2L L86 with direct injection, you now have a camshaft that will allow STOCK drivability, with AFM deleted. Brian Tooley Racing offers part# 2249399130.  AFM delete on these engines is similar. They will use the same lifters and lifter guides as Gen IV engines. You will need aluminum plugs to block the oil passage under the stock valley cover, reusing the stock valley cover.  That’s it!  You can get oil plugs from BTR here.  These tap into the oil holes, or you can get a rivet style plug from summit racing here.

GM PART# 12689035 is the stock camshaft used in the 4.8L/5.3L engine that DID NOT come with AFM.  This camshaft is a direct replacement for the 5.3L AFM cam when you want to do the AFM delete and use standard lifters.  This cam will have a groove in the 2nd bearing journal that is used to supply oil for use in VVT (variable valve timing) that started in 2010.  This cam works just fine in 07-09 WITHOUT VVT, as well as 10+ WITH VVT when deleting AFM from 5.3l engines.  This cam will use the stock single bolt timing gear and bolt from the 07+ engines as well.  As of this writing, this cam is around $118 brand new from GM, you can also get it on Amazon, Summit Racing, so on.  Most all GM parts are on Amazon or Summit Racing. (This cam WILL NOT work for 2005-2006 5.3L Envoy, Denali, Impala SS, Monte Carlo SS or any engine with the E40 ECM those two model years. You must have 3 bolt cam sprocket for those applications.)

GM PART# 12623065. This cam is the factory 6.2L L9H camshaft from non-afm 6.2 in 2009+. Use this for 2007+ applications on 6.0/6.2 when deleting AFM for best matching lobes for the larger engine/heads used on these engines. This cam also uses the stock single bolt timing gear and bolt, works with or without VVT.

2nd option for camshaft; the cheapest way is to find a used 4.8/5.3/6.0 camshaft from 1999 to 2007 Gen 3 engine that did not have AFM. These can often be had for as cheap as $20 online.  There is one small difference. The Gen 3 camshafts use 3 bolts to hold the timing gear on, and the 2007+ use a single large bolt in the center.  On the 2007+ engine you must use a cam gear that has a 4x trigger wheel for the camshaft position sensor.  GM Part# 12586481 has a 3 bolt flange, and 4x trigger and will do this task and costs about $25.00.  The gen 3 camshaft option WILL NOT WORK if you have a 2010+ with VVT.  In that case, use the previously listed GM PART# 12689035 camshaft.

3rd option for camshaft, is to purchase an upgraded performance camshaft.  If you go this route, such as a COMP cam, you can ask for a Gen 3 cam grind, made on a single bolt core.  You need to let them know your intention to remove the AFM lifters, and you need all the intake lobes the same, and all exhaust lobes the same.  Some cam manufactures are making camshafts to be used with the AFM lifters, so be sure to get this right…  On the 2007+ trucks even the smallest performance camshafts will need a custom tune to get it to run perfect. You need to find a local tuner or dyno shop to talk about options after the cam install.

Camshaft sprocket bolt part# 11561283 for single bolt camshaft. This is a one time use bolt according to GM, its about $4.00

2007+ All Vehicles MUST use a 4x cam gear pattern.  You can get this gear for a 3 bolt camshaft, or single bolt camshaft. 2010+ will have VVT Cam Phaser.