I thought this was a interesting read (although it's from the internet and I posted it previously on this thread). It explains SS bolts are around a grade 2, as mentioned by Newc, marine are more like grade 5.
https://www.boltdepot.com/fastener-i...materials.aspx
Although this was a conversion about bolts, I feel like I learned something more.
To add more to the conversion for conversion sake. Grade 8 hardness is not good for anything that has shear force on the bolts (like flywheels). Grade 8 is strong but very brittle.
I guess in conclusion, regular steel 5 grade bolts are good to go. Also I'm not worried about it that much in most situations that are not that dire using ss and some anti-seize regardless of the "factory" torques (outside head bolts).
Don't fool around with flywheels and bolts though! When in doubt give Roy a call.
http://fordscript.com/