http://www.castrol.com/castrol/sectiongenericarticle.do?categoryId=9009747&co...Now take a deep breath and realize that different parts of the world run to different oil standards.
Performance Levels
• Exceeds latest API SG/CD specification
• SAE 20W50
If my guess is right and Heroicseven lives in the Far East or India, then this oil is appropriate for the Savage and likely contains more ZDDP than our diesel oil does. SG and CD are the car/truck specs from like 20 years ago -- which are a good fit for the Savage engine.
I could also be very wrong where he lives -- but if he his buying Castrol GTX in 20w50 that is both car and diesel rated on the same bottle, he likely doesn't live in America.
Here's a listing of the places this oil is sold.
http://www.google.com/cse?cx=002683415331144861350%3Atsq8didf9x0&q=Castrol+GT...This bottle strongly reminds me of what oil used to be before the US Government began fiddling with it. Strong formulations, lots of ZDDP and detergents, and a lot less expensive.