Actually Amsoil did invent synthetic oils & lubricants for internal combustion engines. The company founder was a fighter pilot who figured he could use a variant of aircraft synthetic fluids for auto's, trucks, etc.
STINGN, you can use any type of oil you want, but I would recommend synthetic. As for Amsoil, their products are second to no one. And don't be misled by a company in the above link that won't list any lubricant oil company who won't pay to be included. Aside from Amsoil, Royal Purple and Redline (who also are not listed )also make fluids that will work for ATF+4. OI know this for a fact because people I know use these products in Mopar Transmissions, etc on the drag strip.
I'm also wondering if you've been paying attention here?

JJsKJ is a Amsoil dealer from Southern California and fellow LOST KJ'er, so I would also recommend buying through his site;
HotRodOil.com. Ordering from JJsKJ (John) your items will ship from a local warehouse in the Chicago area. you'll get your stuff quick.
And don't forget to ask JJsKJ not what he sells, but rather what he uses in his KJ!
PM me if you need filter #'s, etc. One last thing, the Amsoil Eaa Air filter has no equal. Mainly because their air filter doesn't need to be oiled like the garbage K&N sells.