Not sure if these will be helpful for you guys or not. Forum seems to be slanted more at hot rods and drag cars, but be useful for the late 60's-early 70's musclecar conversions
http://www.racingsportscars.com/
http://www.historictransamimsa.com/index.html
http://www.trans-amseries.com/
http://www.pbase.com/mwphoto