sam i don't see how they can say you copied their work. i mean they copied what GM out out back in the 60's and what's on every nascar currently. so i doubt there will be any copyright infringement. they won't go after a small fry trying to save $ using original GM parts.
my friend is an artist... he chopped the merc himself with no prior chopping experience. learned alot on that one.
here's a link to the 52 he used the same gas tank in. brand new instead of used though.
http://808speedshop.com/GALLERY.htm
keep up the good work and keep us posted.