I have torn a few apart with bad cams lately and the bottom ends and stuff look new, even the two that had 300K miles.

The 392 cam is cheaper (I paid $68 from the dealer on the last one VS $177 for the 5.7 cam) and since the vave springs break anyhow on the 5.7 it would be a good idea to upgrade to the 392 springs. You get a way better cam for next to nothing when upgrading this way. Make sure to order the 392 automatic cam if you need MDS and 392 manual trans if you do not want MDS.

Honestly I think the cam goes bad because a roller quits rolling and starts sliding so replace the bad lifter and check all the others to make sure they roll real nice and smooth or if the cost is no concern get all 16 lifters new.