Oil change and a funny noise

[JeffChalupa]

I just recently changed my oil myself for the first time in my 88 towncar. I usually have the quick lube places put in 10w30 but i heard that 10w40 was better for the 5.0/302 engine. So I replaced the oil filter and added 5 and a half fresh quarts of 10w40 oil. Started fine and runs fine. But while the engine is running, mostly when its idling, i hear this faint scratching noise in the background. Its not in a rythmic pattern. Its rather sporadic. I have no idea what this is. Also, it never has done this before this oil change

[Towncar]

I started writing this awhile back, then my pos laptop died. I gave up on Firebird and installed Firefox. After many tweaks, etc. I'm back here.

The only "scratching" sound I've seen under the hood has been belts and pulleys.

You may get a muffled fluttering from your PCV valve.

The songs of eight fuel injectors clicking open and closed can be heard if you get real close.

If you have an air pump (smog device), the pump itself, or the gulp valve may be making some scratching sounds.

Off the wall shit:
- Bent dipstick hits the crankshaft counterweights.
- Dipstick not inserted fully, or in the wrong hole.
- Squirrel's tail caught in filler cap gasket, he gets tired and scratches intermitantly.