427Z06, Terry said I could use M1 5W-40 without any problem for the cleaning phase. However, the rinse phase does require mineral oil and that's why I'm now using Delo 400.
IIRC, I believe I read someplace it was not a good idea to use AutoRX with M1 5w-40 since AutoRX's esters would then have to compete with the esters already in the oil?