The Mopar A-body, from 1963 through 1976, and including the 1964 1/2 through 1969 Barracuda, was largely consistent over that period. In particular, the 1967-69 Barracuda was what we call in the auto industry a new "top hat" on the existing (but refined) 1963-66 A-body underneath the exterior sheet metal product content.
Depending on which 1967-69 Barracuda you are building in scale, you could also look at the Revell 1968/69 Dart GTS chassis (with a reduction of 3 scale inches in the wheelbase), the MPC 1971-76 Duster and Demon/Dart Sport kits, and the AMT/Ertl 1971 Duster 340 kits for a chassis setup. I have not tried any of these, and there were year to year refinements in the 1/1s over that period, so this is all theoretical info, needing to be confirmed by 1/1 scale Moparisti who are more knowledgeable than me, and by pulling out all those kits and doing some fitting/assessment.
Best...TB