I had a custom exhaust shop install mine and it took them 6 hours; which they said was close to record time. They said sometimes they need the car for two days. The techs said they groan whenever a customer comes into the shop saying they want headers installed. They know it's going to be a PITA.
I think they removed the heads to do that if it took that long. It is easier but takes a lot longer. Coming from underneath the vehicle and installing them is a little harder because of removal and install of the forward most bolts but if done in a timely fashion, it could be done in about 2-3hours given there were no complications.
No head removal. Installed from underneath according to JBA installation instructions. A fair amount of time is spent with penetrating oil to loosen the exhaust manifold bolts. You don't want to break the bolts or strip the threads in the aluminum heads. You also have to remove the motor mounts so you can raise the engine a couple of inches for clearance. Download the installation instructions for all the details. JBA (Pertronix) website says estimated installation time is 5 hrs ... but most postings on the internet report the install takes 7-9 hours; depending on your tool supply. As posted by weasalsmopar, if you're doing it yourself in your home garage it may take 10 hrs.; not an uncommon install time for DIY installers.
Makes sense, most for my experience with doing headers has been on trucks where there is more room, didnt think the process was more in depth on our chargers because i have seen people on youtube do it without doing the motor mounts, just wiggle along and have an extended electric ratchet and you could pull them out. Another thing i do different is during the week leading up to headers is when i soak the nuts with pb blaster, usually had great luck getting them off with that prep
