MALIBU Is this a piece of a lifter?

It's either a valve spring keeper or It's a chunk of valve stem seal. I can't really tell for sure from the pictures. Is it fossilized rubber or is it metallic? Will it stick to a magnet? If so, it's a valve spring keeper. You should be able to see the valve spring keepers at the top of each valve spring, around each valve stem. There are two keepers per valve/spring.

That's a keeper

Just 454 swap it.... 🙂

That looks like a valve stem keeper that's not keeping any longer. Where did you find it? Never mind. I saw it was already washed into the intake valley with the oil. Pull the valve covers.

They come in pairs for each valve, just like in Texas82GP pics above. If one is missing, the other one MIGHT keep things together, but not for long. INSPECT the valve train everywhere. Check for sticking/bent valves or other valve train anomalies. Cracked/broken springs can let keepers come loose as well. Good thing that good ones are still fairly cheap. I'd consider replacing all 32 of them, just to be sure. While you're in there anyway. Also, check the push rods for straightness (roll them across a pane of glass or machined flat surface.)

Everything 69hurstolds said (except the 454) and be prepared to check the timing chain set it is likely bad enough to allow that to happen.

Valve keeper "since your car isn't missing and not blowed up someone could of changed valve stems seals by removing the valve springs to do that you compress the springs and take the valve keepers off ( out) if one was droped into motor it could end up in the oil pan or somewhere inside the engine possibly harmlessly..or of course it it got into a timing chain it could cause some problem or get kicked to the bottom ...about the keeper there's 2 ( a pair)on each valve stem 32 keepers per 8 cylinder two valve/cyl engine.double them figures for 4 valve per cylinder motors ( quad motor etc.) I can say a motor might run with one missing but it will not hold any time before it let's go of the valve and engines have been ruined..by this happening maybe you should look under the valve covers and make shure etc.!...Though it's not likely you are running a motor with 1 valve only having only 1 keeper . A tip here for mechanics working on valves is to keep the keepers on a neo magnet so they don't drop places untill you install them. I sometimes put waxy grease on a screwdriver tip to hold the keeper untill I press it into the retainer were more grease sticks it to the valve while releasing the spring compressor locks the Valve and spring retainer together..