Varies, its around 5 bucks a quart where i get it, this is what i run:
http://amsoil.com/products/amf.htm

Ive used amsoil in everything i own, always synthetic. I had it in my race built AOD and in my 306 roller in my mustang, my truck now, my parents cars, even my lawnmower. They even make 100 to 1 2 stroke oil that performs better then the 30 to 1 oils.

 

Id expect the time between oil changes is longer with synthetic then? Ive always been a petroleum man so I really don’t know the results of synthetic brands.

"even my lawnmower" <- lol

 

There a guy on there that has a mack truck, he went 403000 miles before an oil change, and when they tore apart his motor it looked as if he was doing a regular oil change every 30,000 miles, like your supposed to on a disel. You can go longer, i like to dump every 20 hours, i really don't have to, the oil coming out still looks new. On that disel truck the cylinder still had most of its crosshatchings, now thats a real world test as to how good this oil is.

 

Yeah I dump my oil usually every 2 - 5 rides depending on the length of them.

 

Hey thanx guys, i think i am going to run the Spectro 4 since its a little cheaper and it seems to be an ok oil. I will keep in mind the Amsoil, thanx again