1967 Chevellle SS396 production numbers: 59,685 hardtops + 3,321 convertibles = 63,006 total.
1967 Pontiac GTO production numbers: 65,176 hardtops + 7,029 coupes + 9,517 convertibles = 81,722 total.
http://chevellestuff.net/1967/style_prod_no.htm
https://en.wikipedia.org/wiki/Pontiac_GTO#1967
(edited to correct the total number of SS396 cars.)