I used Castrol RS in my BBC LS7 Cobra and it was better at maintaining
oil pressure at race temperatures exceeding 260F compared to mineral
oil and some semi
synthetic race oils this is from the hot temperature perspective.
I think it best to follow the manufacturers/engine builders recommendation and a good way for me to go is my 600bhp plus engine has been dynoed on Delo 400 mineral
oil and will do some med to fast road miles on a fresh batch for 300 miles, then I will use semi
synthetic Schaeffer race oil for the track!
I dont think you can do any harm with a full
synthetic and if you run a flat tappet then add some
zinc additive as some oils have less than needed. I keep wanting to put the best special oil in my engine irrespective of cost but I keep seeing the race guys keeping it simple and run a good quality semi synthetic or mineral oil and change it often.