So you have a shift box from either a 70-74 E-Body or 71-74 -Body.
SHIFTER MECHANISM IDENTIFICATION
All factory (original equipment) Mopar/Hurst 4-speed shifter mechanisms can be identified by the four digit number on the reverse lever, which is the longest of the three. 1968-75 A-body and 1968-69 B-body uses #6353 (as does the later truck overdrive), 1970 B-body #7174, and 1970-74 E-body/1971-74 B-body #7180 (which happens to be stamped upside down). All of these have 5/16" holes for the reverse linkage rod attachment. A common Hurst aftermarket/replacement shifter mechanism (for most A & B applications) has #6370 on the reverse lever, and utilizes a 1/2" hole and a reducer bushing.