Header install question

So I bought a set of TTI long tube headers for my car, 1970 Dart Swinger 340 4spd. I havent installed a set of headers in about 30 years, so I figured Id take it to my local hot rod shop to do and consider it money well spent not having to lay on my back and fight with them.
The shop has almost two days into the install of these headers. Is this realistic hour-wise? Lord knows I know that headers can be a PITA to install, especially an A body from what Ive heard, but I thought an experienced shop with a good hoist could do it better/quicker than I could, and Im now on the foot for a huge bill for this.
Opinions, is this far too long for an install? Or is it par for the course? I figure the money that I spent on TTI headers should be worth an easier fit/install than a cheaper brand; if it takes this long to install TTI's, I could have spent less money on headers and still paid out the butt for install.
And yes, I spent the extra money and bought the TTI Z bar also(which they recommended). So $2000 for headers and Zbar, and still take just as long to install as a cheap set of Blackjacks??