They make a correct tool to do the line and fittings, but this worked really good, I tried it today and worked very well!!
http://ls1tech.com/forums/15193388-post19.html
At the shop we have the kit to do this. I completely remade the fuel lines on my car, even the quick connect flare on the steel line.
I purchased the Dorman kit with all the fittings and extra vinyl line. Getting ready to redo fuel lines on both my Cougar and currently my dad's 2000 Impala LS. It's good to know it works well.