Recommendations for good "A" street header

I installed the d453 from dougs in my 70 duster last year. With the 4 speed and manual steering I had a few tight spots. Had to put a couple dings in them for clearance around my torsions bars. One per side from what I recall. Your results may vary as I have the older style biscuit engine mounts and with 50 year old cars and factory tolerances, you may be just fine. I believe the 72 dusters have the spool style so that may make a difference. The drivers side header is not fun to get in.

the clutch linkage is also very tight to the header and you will have to modify your clutch z-bar. You can use the old big style starter, but the Dakota/ram mini starter fits much nicer with the headers.
Had to lift the engine up about 2 inches for the header to get in there. The car also has to be up in the air quite a bit probably have to jack it up about 2 feet or so. Good luck.