When parts walk away......

Doing a top end swap,on my 360 Magnum.Bagged ,tagged every part,upon dis-assembly. Been working,as cash allows. Sure enough, the last goodies from Summit shows up,things disappear.(lol!). Lost two lifters,picked up two new ones.Sure enough,they show up,after assembly. I know some of you,have similar headwracking experiences. Share yours,please.