Well I will try again to say some NEW information, less then 1 year old. I pulled down the other posts I had written because of the attitude they seemed to impart or attract, I am not sure which.
The hogwash responce is very often my own response, however, I use it less now then I used to, because I have been wrong to many times.
The reality is that not all oils are equal, not even synthetics. The EPA regulations have forced the petroleum engineers to recduce the amount of zinc, and some other wear reducing additives in "S" rated oils, to meet emissions standards.
This reduction has had an effect on the high load wear areas of the engines. American made flat tappet engines are particularly affected. IE the cam and lifters, and in some cases even the bearings. This is not a big problem for roller lifter engines and most gas sniffin engines are rollers now, and since 1995. Some of the overhead cam engines aren't, but most of them are imports or designes like the imports, that have a very large surface for the cam and lifters as compared to an old design american engines, so it is not a big problem for them either.
The above is true for mineral and synthetic "S" rated oils recommended for new cars still in warranty. That is why we see the oils like Max Life. They are more like the old oils were. And are not recomended untill after warranty. Most of this is on the website
www.bobistheoilguy.com . The problems with "S" synthetics and cam wear is that they never had much if any zinc in them. I have not seen anything about why, and I understand that that has been changing, at least in some brands.
CRANE CAMS, COMP CAMS, AND SALEE CHEVROLET all say the same thing. They will not warranty a camshaft that is run in on any synthetic oil. They recommend that if you switch to synthetic later, that you run GM EOS continually. (Some of them require EOS as a prelube and in the first oil) I am not the one saying this, I am only quoting (yes, with some editing because of space and memory, mine that is). This is a result of research done after about 4 cam failures in two engines with Amzoil. All in less then 4000 miles. All in the last 3 years, one last year. They had beafed up valve train, but not enough to cause that rate of failure. (One was stock Corvette aluminum heads. But running with a flat tappet cam and lifters.
Mobil 1 says in their technical material that they add a small amout of mineral oil back to the Moble1 to provide some seal lubrication. They did not do this a first and seal failure became a problem (in the 70's).
There is a lot more to say, both pro and con. but it is late, so I am going to wind this down.
I will add this though. If you look at the Cummins B series cam lobes and the size of the lifters, add in the max RPM and the valve spring pressure, the load on the cam is much lower then the adverage gas sniffer, so the synthetics would not be as great a problem even if they didn't have some of the additives. I also believe that it will be found that the "C" rated oils are a different ball game from the "S" rated ones. I don't have any data on that yet, but I will look for some.
Also the fact that so many of you are running syntheyics of different brands and are not having problems says a LOT. You have made this old dieahrd take a different look at the situation.
But please let us not label something as wrong just because it don't make sense or don't fit what we have thought. Check it out, and pass it on, we might learn something new.
By the way, the FRANTZ filter is a very good bypass filter. I still have two of them, one of which I bought in the middle 60's. I didn't know if they had survived the decades since then, so I was glad to hear that they did.
Attention: TDR Forum Junkies 
My wife is offensive enough!! :-laf :-laf I'm just stating my opinion, and experiences in past repairs. I don't want to be the cause of this getting out of hand- you can!! :-laf :-laf ONLY KIDDING :-laf John 
