[Ron Sutton]

I also doubt they were grade 8 bolts. They would not have broken at 20# of torque, even if they were cross threaded. I use grade 8 bolts everywhere on my cars with two exceptions ...
1. When I need the bolt to break first in a crash to save the part. We usually run grade 5 in these situations.
2. When I need something stronger than grade 8, in which case we run NAS or something engineered like ARP.

I would suggest you use grade 8 bolts everywhere ... especially on such sensitive areas as ball joints.

Only as a guideline ... "usually" ...
* Grade 8 bolts are gold iridited.
* Grade 3-5 bolts are silver cadium plated
* Grade 1-3 bolts can be black oxide coated.
The common exception is allen head cap screws which are "usually" black oxide coated even in grade 8.

The best tell-tale are the markings on the head of the bolt. Refer to the chart below ... and note the strength differences in the ratings.