To the OP, if you think that is sludge in that drain pan, you need to look at the pictures pishta posted. That oil is just oil that's picked up what was left in the engine from the last oil change and simply changed color.
I did have the cover off of my engine and there was baaaad sludge and I posted a coupla pix 5-6 weeks back; I used Rotella for the dispersants to get more out. I am sure I still have plenty inside. My old 351C came from the boneyard and the Torino we pulled it from had Quaker State stickers all under the hood; that was back when QS still used PA crudes as a base. It was not nearly as bad as Pishta's, but it was on its way.....
Reminds me of a guy I was in the Navy with; a good ole Cajun' for LA. We were chatting about cars one day and he mentioned that his Pinto with 31k miles was not running too well. I aksed when he last changed oil and he got a quizzical look on his face and said "Change the oil?". It was like molasses when I went to change it for him..... he was a character but not a mechanic....
