'68, IIRC. The '68 TransAm Camaro offerings in mid-year production included DP carbs. The '69 L88 may have been the earliest production use of DPs, and one of the only ones. (Definitley not on 428 Shelbys in 1967! Or the "hundreds" of single four-barrel Hemis in 1964 and 1965!) The center-squirter tunnel ram carburetors were the predecessors and they were available early '68. If I had time to look them up, I'm sure that the magazines of the era ran articles on them.
__________________
|