Keep in mind (not really directed to Herb....) if you upgrade the bolt rating, it ALSO requires a higher torque value to maintain the correct clamping force within the elastic limits of the fastener.
Common issue is, "well hey, I put in better hardware, but it still failed!!", person never properly torqued the better hardware to an appropriate torque valve within elastic range.
I'll stay out of lubed vs. dry threads, rusty vs. clean threads........