These are/were a New/Old set of Blackjack Headers. Part #3006. Manufactured in 1989 to fiit Camaro 70-81, 64-71 ElCamino, 71-74 Fullsize cars.
They fit a G Body perfectly. I had them on a 396 in my '79 Malibu, and have pictures of them mounted on a block in my ElCamino. 1 ¾" tubes, 3" collector. They've been bead blasted. No damage to the bottoms of the tubes. One small dent for frame clearance on the #6 tube. Driver's side motor mount was 'relieved' for clearance. Will include if needed. Prefer a local sale......do not want to ship these. $125. Price lowered to $100