Here's a few sites that will help if you are not sure about bolt grades and Harleys.Most socket head bolts on Harleys are grade 8.

Bolt Depot - Nuts and Bolts, Screws and Fasteners online (http://www.boltdepot.com/)

Grade 5 vs. Grade 8 Fasteners (http://www.rockcrawler.com/techreports/fasteners/index.asp)

Bolt Grades (http://www.volvospeed.com/Repair/boltgrade.htm)