Hello to all! I've been lurking these forums for a while and decided to join. So much information here and I'm still trying to get my head around much of what I've read. Anyways I have two vehicles, one is my daily beater 1998 Cavalier, 2.4L DOHC. I use primarily Castrol GTX 5w30 and a SuperTech 3506 or AC Delco PF-46 filter at 3000 - 3500 mile change intervals. Burns less than half a quart between changes and runs like a top at 155k miles. Other is my 2000 F-150, 5.4L SOHC with an ATI ProCharger P1-SC @ 13 - 14 psi. Has 54k miles. Dyno'd 350 whp, 425 lb-ft with a slipping belt at 10 psi. I've always used Mobil 1 with a Motorcraft FL-820S filter since the first oil change. Truck is rarely driven now...few times a month usually to meets or to the track. Oil is changed every 4 months reguardless of mileage. Any tips or info appreciated. Never done a UOA but I'd like to do one on the truck at some point in the future.