[Skippermark]

Originally Posted by ApS

https://www.motorsportmagazine.com/a.../55/castrol-r/

Red Line synthetics arrived on the racing scene in 1980, but had only a low level of market penetration.

https://gmb.net/blog/synthetic-vs-co...%20the%20years.

Thanks for the links. Now I'll have some good reading to do before bed tonight.

My son has a couple older muscle cars and only puts Red Line in them, but he said it's not API approved though the quality exceeds their standards.

I had never heard of it until he told me about it.