what all needs to be replaced. i understand i could do everything from the cam up but i would like to know only necessary first.

 

Just it, and gasket

 

I explain the procedure in thi post:

https://chevroletforum.com/forum/2007-2013-gmt900-109/my-5-3-afm-rebuild-experience-84428/

 

I would like to know how much you ended up doing, & what results you've had? The primary thing I'm still trying to dig up further info on is if you did anything with the VLOM, & if you replaced it which did you go with?

 

You could do as little as just changing the one collapsed lifter.
Does your truck have AFM/DOD