Hello,all. New member here. I found this board thru a member of MCML(Monte Carlo Mailing List);and have been lurking for a couple of weeks. After reading a bit,I've let go of some preconcieved notions I had about engine oil(I thought I knew what I was talking about!),and this forum has dispelled some popular convictions and myths I had. I do have to say,I'm now confused on what weight,type,brand,etcetera of oil I should be using,and I'm hoping some enlightened members could show me the way! Here's some of the cars we have,a little info on them,and what I am contemplating: *1986 Monte Carlo SS- 305 HO,140K on the clock. Only smokes a little on start-up(valve stem seals),still pulls strong. Some bolt on mods,-headers,intake,etc. Currently running 10w40 Maxlife. *1975 Corvette- built 355 10:1 compression,big cam,etc... 20K on rebuild. Previous owner(bro-in-law)ran 10w40 Pennz since break-in(to 17K),we switched to 10w30 M1 after purchase. Car currently leaks M1,and burns a little,also *1979 Z28 project-car has been abused,and neglected(could rival the pics of the varnish on that import that's on here) . Just bought/rescued. Approx 173K on odometer. Currently running Castrol GTX 10w40. *1980 Z28 project- see above^. *1987 Chrysler LeBaron GTS turbo. My first turbo car,given to me by a friend,had a blown head gasket. I changed the head gasket(uggh,never do that on a turbo 4-banger again!). Car has 86K on it. Fresh 10w30 GTX. Ok,I know...I have to many cars,and not enough money! Or is that brains? Anyway,I looked through the phone book,and found a Schaeffer dealer close,along with an Amsoil rep... Here's my plan: The 2 most important cars to me are the SS and the Vette. After speaking with the Schaeffer rep,he suggested 15w40 for both. I was gonna do a Neutra purge on the Monte,then switch...Auto RX for the Vette,then switch. On the Z28 projects,I was gonna do the Amsoil flush,then follow with Delvac 1300. On the Chrysler,well...I don't know.It's not in the greatest shape,either. It's a daily driver/beater(so are the Camaros,really).I was thinking of doing either a Neutra Purge,or making it a test mule for the Auto RX before the Vette. Not sure what weight,/type/brand of oil,though... As for filters...After following the filter test thread,I went with a K&N(seemed to offer an acceptable flow vs. filtering compromise),but I'm unsure on what to use on the other cars. All in all,I don't mind spending a little for quality,especially on the SS and Vette. For the others,quality is important,but not as much. Bang for the buck in both cases,but I'm willing to spend more on the aformentioned 2. Last but not least,should I do a UOA before and after on these vehicles? VOA on anything? Any other advice/ things to do before I switch? Am I on the right track,planwise? Any/all suggestions woulld be greatly appreciated! Thanks for hearing me out,and I apologize for the long first post! Randy Gaines- oil nut whose glad to find other neurotics online!