Does any one know much about the SYN LUBE oils....apparentley this oil is not petrolium based, but a tru synthetic oil, unlike petrolium based synthetic oils

I have used AmsOil and Royal Purple which are both true synthetics and have been quite impressed with them.
Have not tried Syn Lube.

Here in the US, there are a few companies that actually produce Synthetic Oil base stocks. The stock is then sold to different companies and those add their additive packages to them blend it up, package and sell as Proprietary name brands. Most full synthetic oil is all alike, just different “trade secret additive packages” blended into it.
While I have never heard of Syn Blend, I am sure it will suit your needs quite well. I have used Amsoil for quite a few years and have ran it up to thirty two thousand miles before changing and could have ran it longer with just installing a new oil filter and adding that amount of oil back in the engine.