Here's the real deal for those considering the $170 Hedman headers (I got mine from Summit)
First: YES, they do fit with NO mods. Some helpful hints:
1. Use a two post lift. You'll be going from the top and the bottom of the car as you work, and back and forth
2. Disconnect battery, remove passenger side front shock
3. Disconnect (auto trans) kickdown linkage swivel bracket, remove spark plugs
4. Remove starter and factory exh manifolds.
5. Remove front motor mount bolts
6. Use a floor jack and jack front of motor motor up as high as it will go (WATCH RADIATOR SHROUD WHEN YOU DO THIS!). Install passenger side header (Watch that you dont upset the balance while doing this if your car is also on a 2 post lift)!!
7. Remove only the suspension componants required to get the driver header in. (Look and use your common sense)
This is the hardest part: It will take 2 folks: Lay on your back and hold starter in place between the new header and the engine block, (DO NOT bolt it in yet), while you slide the header up into place and your buddy helps from the top to hold the header and also help get it into place while you slide the header from bottom to top. You'll never get it done with the starter bolted in place. Move the starter around while the header is being put in place. With header NOT bolted in place yet, snug the starter down onto its mounts first when you get everything in its approximate place, then place in the header gasket and snug down header bolts. This procedure is a ***** trying to manhandle the heavy starter around while getting the header in place, but it only took about 5 minutes to get the header in place using my technique
Put everything back in place. Wipe headers down with degreaser. Heat up engine BRIEFLY a few times to set the factory paint on the headers (It will still blister though in some places)
Drive and retourque header bolts a couple of times after the first few times driving
I have a 71 Cuda, Auto, PS, and the above worked for me with NO mods to the headers