[Oldsguy]

Alan, I own a '69 Delta with a 455 and this is what I did. I went to the junkyard and bought a driver's exhaust from different car with a 455 engine that has a rear exit collector and modified it by cutting the end (collector part) and rotating it 90 degrees so it dumped toward the firewall and left enough clearance for attaching a downtube. This was necessary because our Deltas have the steering box behind the upper control arm. I had a local shop that could weld wood if necessary weld it, they are REALLY good. I cut off the crossover portion of the passenger side exhaust manifold and had the same shop weld a heavy gauge plate in place. In essence I ended up with two manifolds that allowed true dual exhausts all the way back, 2 1/2 inch pipe. They are similar to the famed "W and Z" exhaust manifolds from the factory that cost lots of money, I don't know how much they go for now. That's what I did, hope this helps.