After 35 years back to where i started need exhaust manifold help
You can find 72-74 340 / 360 A body manifolds at pretty reasonable prices and just order head pipes that fit the manifolds you use. They are not nearly as expensive as the 68-70.
That is what I did on my 69 Cuda with a 360 / 727. I sawzalled the headers off.
I ordered my exhaust from Waldron & it was very reasonable.