I get a lot of questions on my 69 Vette about the flares. I am also helping a friend right now get wicked wide with his 81. I created a quick "How To" page on my site.
He just ordered his 18x9.5 fronts and 18x12 rears for the car last night. This car is going to rock! He has also ordered his full suspension kit to give it some handling to match the 406 small block, 3:73 gears, and built 700R4.
http://mcspeed.homestead.com/Flare_Install.html