I bought a tool today that is worth the money to buy and always been looking to do this.I bought the Mastercool hydraulic flaring tool kit and even came with the 37 degree kit and GM jiffy tite adaptors that are purchased separately.Bought it out of an estate auction,used once for $250.00 which goes for over $400.00 brand new.I have used one before,slick tool to use and won't use my manual version anymore.I have a few projects to use it on and will pay for itself in the long run.This is what I am mentioning
http://www.mastercool.com/pages/flaring_tools.html