Cadillac 60 Series 1963 Shop Manual page 594

APPENDIX 17-1
BOLT AND NUT IDENTIFICATION
BOLT STEEL CLASSIFICATION
G. M. MATERIAL NO.
HEAD MARKING STRENGTH
260-M
280-M
300-M
(None)
(120°)
(60°)
Standard
Medium
High
HEX-NUT STEEL CLASSIFICATION
G. M. MATERIAL NO. MARKING STRENGTH
Conventional Type
286-M
301-M
1
USUAL
T
OPTIONAL
(None)
(120°)
(120°)
Standard
High
Prevailing Lock Type
(Stover)
B
(None)
(120°)
(60°)
Standard
Medium
High