The modified aircraft became known as "Clamps" (two of the original 14, 64-0564 and -0565, were diverted to Heavy Chain in August 1966).
Pesawat modifikasi tersebut dikenal dengan nama "Clamps" (dua pesawat awal dari 14 unit, 64-0564 dan -0565, dialihkan ke Proyek Heavy Chain pada Agustus 1966).