brass washers for manifold

Get that man a kickdown assembly.... Quick!
Unless... is your Dart a manual shift?
If so you do not have a kickdown assembly.

"Unobtainium" lololol I Love it!

So.... this is my 2 cents worth.
Hope it helps and if not ask us again.
I have 30+ years of working on and owning slant 6's. I don't race 'em anymore... just cruise now.
I don't know everything, but do know a pretty good amount and love to help anytime.

Later,
Bruce B.