I have a book with the Chrysler production numbers for each year for both cuda/chally.
it says 1971 was the last year for the vert: chally 383 4bbl auto was 126 verts.
chally 383 4bbl 4speed was 41 verts.
1971 cuda/barracuda vert numbers: barracuda 383 4bbl auto was 9 verts
" 383 4bbl 4speed was 10 verts
" 383 4bbl 3speed 0 verts.
gran coupe 383 4bbl auto 0 verts
gran coupe 383 4bbl 4speed 17 verts
gran coupe 383 4bbl 3speed 0 verts
CUDA 340 4bbl auto 102 verts
" 340 4bbl 4 speed 30 verts
" 340 3speed 0 verts
" 383 4bbl auto 87 verts
" 383 4bbl 4speed 33 verts
" 383 4bbl 3 speed 16 verts
" 440 6bbl auto 12 verts
" 440 6bbl 4 speed 5 verts
" 426 auto 5 verts
" 426 4speed 2 verts
Total challenger convertibles for 1971 was 1,793
Phew.................hope that helps !!!