Ford 5.0L upgrades!?

Hows it going yall, i have a 96' F-150 and im lookin at cams and gear drives and pretty much that whole area. Im looking more for longevity and sound than i am performance right now since its a truck. I know cams and drives give that awesome tone, but i have heard certain mixtures of brands or styles can really put a number on the life of the parts. Im not educated on 5.0 too well and im just looking for some helpful opinions. So far i only have flowmaster 40's on it, im lookin at putting a new free flow cat to get rid of the 2 cats, and holley hooker headers, plus the cams...and ive heard somewhere, if i remember correctly...from horsepower handbook, that for 5.0's it is possible to get a gt40x heads and put them on mine (im not 100% sure on that though)...let me know what you think