There is no problem using high-ZDDP/Zinc oil on any stovebolt engine (I think).
However, it is not needed on stovebolt engines 216/235/261 after break-in.
I use a high ZDDP break-in-in oil on my newly rebuilt stovebolt engines.
After break-in, I use the Shell Rotella 10w40 or 15w40 after that (whichever is cheaper).
Are we heading into another round of discussion of ZDDP-necessity in stovebolt engines?
