I've been running Rotella-T 15w40 in my stock '50, 215 since
I brought it home 10,000 miles ago. I rebuilt the engine
about 5,000 miles ago and continued to use it for and thru
the break-in.
This isn't a laboratory study that's going to be put under
the microscope, these are just old trucks, which will run
just fine with just about anything that will lubricate them.
Don't be so dang particular about what kind of oil your
pouring into them, just keep them full.
dg
