I have use rotella in my street car/n/ss car. the engine has over for hundred passes and a bunch of street miles on it.it has a racer brown 562 lift flat tappet cam.no valve train failures ever and only one set of rod bearings and valve springs on those passes and miles.the car is just as fast as it was when the engine was first installed. sound like a winner to me on this kinda combo.but my race engine im about to install in my 64 330 has a roller cam so it will get whatever the builder say to use.my guess royal purple.