horses for courses, and we all have our favourites, but......i will never ever use castrol oil again. not even in a runaround.
years ago when we were rallying gtx was bandied around as the best oil to use, duckhams hypergrade
was a green oil back then, in colour not for any environmental reasons
we used to get trouble with cams wearing and followers breaking.
a friend who also rallied at the time was a dealer with silkolene oils.
he told us to get rid of the castrol as it breaks down under extreme conditions
when we swapped over to the silkolene (as used by will gollop back then) we never had any more issues with cam wear. ever.
i know times change and things are not the same but bad experiences stick with you.
but if cars have done 300k on gtx then it can't be as bad as it used to be