So I put RGT 5w30 in my 1984 F150 302 which I believed was neglected. I noticed big chucks of carbon on the dip stick. I have from experienced had a clogged filter problem with my other truck doing this. Around 500 miles the oil pressure started to drop so I swapped just the filter with a stp extended life filter with synthetic media. Noticed all the carbon in the can. Filter media looks ok but I didn't want to risk it. My other truck got to a point where its bearing where screeching. After I changed the filter, oil pressure went back up.