What size is the bolt that holds lower front Shock

need to find out what size is the bolt that holds the lower shock into the control arm on a 1965 plymouth Belvedere?
thanks

7/16 X 2-1/4 or 2-1/2 I see both lengths and both fine or coarse thread, self locking nut, without lock washer usually. 2-1/4 bolt will extend through the nut about 1/4 inch.