So I've been lurking a while and have digested a little over half of this thread.
I'm sure most guys know this but in case some don't the fender extensions on the Dart fenders came in two varieties from the factory one a pot metal version which my 72' Demon had and one a lightweight plastic possibly 'glass version. There is quite a bit of weight difference if you can find the light ones. The ones I found were on a set of 71 Dart/Demon fenders.
Had a 70 340 Swinger and a 71 340 Demon, both had fiberglass extensions, 71 /6 swinger had pot metal...I have toyed with the idea of making molds for fiberglass ones...
Faster, Faster until the thrill of speed overcomes the fear of death...
71 Swinger - slowly collecting dust/parts 66 Belv. II - just a streetcar 88 Mustang - turbo LS beater