Assembly-line calipers on late '66 into '67 GT350/GT500 typically had Kelsey-Hayes casting numbers like C7ZX-2B120-A or similar. Look for the reinforcing bar on later units (post-Jan '67), plus 7/16 hose fitting vs early 3/8. Your dates suggest you'll find mostly the later ones.
Some also had a small "KH" oval cast in. Originals differ slightly from service parts, so double-check those fine details. 😊
Some also had a small "KH" oval cast in. Originals differ slightly from service parts, so double-check those fine details. 😊