I think this is a useful thread because most people really don't have a good understanding of which oil they should be using and why. Since CompSyn sells engine oil, I think he has a natural interest in it and reading misguided recommendations must bug him. It would be well worth your time to read the links that have been posted as they do contain useful information.

Another excellent article everyone with an older engine should read is the Corvair Flat Tappet Oil article. The author also sells engine oils (in Bolivia) but specifically does not mention any of his products. He uses Chevron Delo 400 Synthetic 5W-40 (CI-4/SL) in his 1988 BMW and his 1960 Corvair (but I can't find the product data sheet for this oil).

I like Esso XD-3 Extra HDEOs (0W-30 and 0W-40) as these are also Group IV (PAO) oils like Amsoil products but are more economically priced. I also like PetroCanada Duron oils which include Group III synthetics. I didn't mention them earlier because they're not readily available in the USA.

As for WalMart's SuperTech Synthetic, from what I've read on BITOG, it's not a bad oil. See BITOG: SuperTech 0W-30