alot of money just for lifters, cam kit just listed on FB by someone in the VE club $2800 fitted(or what i can make out-seems a bit light on though), includes lifters, cam etc etc, if you went this way you would get new oil pump as well $300 as it has to come off anyway, known fact that the LS engines can be noisier on one oil and not on another (lots of threads on here), used to run penrite 5/40 in the VE SS (L98) was good on it, mileage up a bit now, i run 10/60 penrite (10tenths) nice and quiet does not like castrol, nulon, my maloo hates both and penrite and and i run it on Valvoline full sin 5/30 and is quiet. if you have aftermarket headers and exhaust you can get some noise through them too and its nothing, as jcvhsle has said you could be hearing side noises (pulsing etc) if you can put up a video might make it easier to hear what you are hearing