Sunthetic Oil once Again

[Nicholas Pinto <npinot@ix.netcom.com>]

I promise this is the last time I bring up synthetic oil.  I've learned a hell of a lot
on this posting in only a week.  I think I am going to change to synthetics, but naturally I have a few more questions:

1)  Is it every too late to change top synths??  I seem to remember reading somewhere, back in the '70's, that you needed to run synthetic from the beginning and that you shouldn't convert over.    I have three vehicles that I would like to convert and 2 have some mileage on them.

2) I gather Castrol and Quaker St along with Mobil are the top synths, but is there a good rating on any others, such as Havoline (texaco)???

Thanks, as always!!!

- Nick Pinto