Super Six install on 1974 Dart

Well it is, sure don't look like it is with the carbon that gets built up within it.
I bead blasted the one that I put into my son's truck and exposed parts of the threads...then I had t pick away at the rest of the buildup to expose enough thread so the pipe tap could start. I basically cut the rest of the carbon out with the tap.
Might want to check that if you want egr to work to be sure you got enough flow
Carbon/coking up is a common problem with egr systems, the newer stuff with it will set a code for insufficient flow.
If it don't set a check engine light i'd just about rather see them plug themselves to death. One less headache to worry about.