Packard Forum Index » Post-War (1946-54)

Bottom Line Up Front: Can I use grade 5 washers and grade 8 nuts for the head and manifolds?

I have removed the head and manifolds. They have been sandblasted and will be resurfaced, primed (2000 degree) and painted (1600 degree). Since the nuts and washers will not be painted I'm thinking of using black oxide (900 degree). In black oxide, I have found grade 8 nuts but only grade 5 washers.

I don't know.

But, Max Merritt has head nuts and washers. They also have studs in case you have any that are damaged.

The engine probably has rolled threads where the studs go into the block so important to not run a tap into the holes or use modern over the counter studs. As for nuts and washers, Grade 8 wouldn't hurt but might be overkill and finding them with the 3/4" hex might be difficult as it's not a standard size for that thread as far as I recall. I think 11/16" is the standard size.