[bobcowan]

I agree with Doug. There's really no need to change any of the fastners, unless the don't fit right.

Get ahold of a copy of Carroll Smith's book, "Nuts, Bolts, Fastener, and Plumbing Handbook". Very enlightening. Grade 5's work best in a shear situation. Grade 8's should only be used in conjunction with dowel pins - like bellhousing to block.

According to Carroll, "There is no place on a race car for a grade 8 fastner". Not sure I agree with that, but applications are limited.