Afm

I read a couple of stories with people upgrading there lifters in the models running afm is this only because there running bigger cams or are the lifters just no good?

AFM runs standard lifters on half the cylinders and different collapsible lifters on the AFM cylinders and those seem slightly more prone to problems than normal lifters but if you wish to keep the AFM you have no choice. The collapsible AFM lifters are also not suitable for medium to high lift cams, so when most people replace the cam they also go the extra bit and remove AFM/DOD. That means heads off so adds the cost of the labour involved, new lifters, new head bolts, new head gaskets etc plus also a non AFM valley plate (usually easy to acquire second hand). You can also buy DOD Delete kits with all the required parts.

the older AFM lifters were also prone to ticking a lot - mine were starting to get quite audible so I replaced all of the AFM gear out. Since its a heads off job and you can't reuse the cam, it makes sense to go an aftermarket one, or you can use all standard parts and use an LS3 cam for a reasonable power gain.

Not a cheap job unless you're able to do all of the labour yourself, so probably best to weigh up the pros and cons. IMO it is worth it for the peace of mind.