keep us updated i wrote a how to install shorty header fir the 197 V6 search my topics. it may be lost in the garage, but i think its still a single thread.
http://www.allfordmustangs.com/forum...r-install.html
quick hint have a good set of jack stands.
when u get to the cat bolts ( that hold stock manifold on, they are cast in to the manifild, and go through a flange. CUT THEM OFF you will save a busted extention, a busted knuckle a few heated breaths and alot of time.
cut the one closest to the ground off. the top one will ratchet off with ease.
if u use a torch take out your O2 sensors first!
ALSO
When you do the headers, on the right side the coil mount wont bolt back in. remove coil bend out bracket, then it will bolt in. you’ll see how far you need to bend it
oil stick.
In the way, headers go behind it stock bolt does not fit through header flange, I left mine hang its ok
exhaust sensor, bring out * unhook near air inlet. * take out with old manifold.
Stick in vice, use monkey wrench to get off. It’s a pain.
To remove with the manifold you need to unbolt air box and the thingy mounted to the strut tower.
To get head bolts out, don’t bother with inverted torx
once manifold is removed. Use ratchet (13 mm) tighten down nut as far as you can go snug but don’t break it.
Ratchet another down in behind it get it tight
use 13 mm wrench to back out the nut next to the head, the bolt will turn.
The torx will break off.
To get the manifold off easy use a torch or air grinder, cut off bottom bolt, this will loosen the flange, and the top nut will ratchet off with super ease.
Now with the exhaust sensor tube, take the lower bung off. You will see that it will unbolt, so the female end will go to your new header.
Tighten it up so the tube is 1 inch from the header...
Bolt header on, tighten up there you go!
and yes my stainless headers turned funky colors

feel free to pm me