72 340 pass side manifold

1971 CY Dodge Dart said
What size longtubes did you run, 1 5/8 primaries?

The cheap headers (Black Jack, I think) I put on my 73 Duster were 1 5/8 inch. The TTI's I put on my 67 Barracuda back in 2012 or so were 1 5/8 to 1 3/4 step headers.