Hey Guys been a while since my last post but I need some help

I currently use Mobil 1 15-50 Fully synthetic oil in my Cosworth,

However I can't seem to find this oil anywhere anymore.

Does anyone know where to get this oil or if it has been replaced by another if so what affects could it have n my engine.

Thanks in advance for your help and advise

Zee

 

It's still available off ebay and anywhere else that has old stock. But it has been discontinued. They only seem to do the 10w 60 I think it is now...