trauschu , I see thats a Texas car, your pics looks like its in Texas too, whereabouts are you?
There`s a fairly good size group of us w 69 birds here i Houston (if you`re here by chance), we are prob. 12-15 FGF owners locally....

and we`ll set you straight on how to pronounce "Firebird" , not Camaro...lol

and Yes , I know that Niklas in Sweden added 3 point belts, I can prob, get pics from him ....discs are available as kits and you can get used from other cars , I think i have heard Novas , to replace...rubber parts you can get from parts houses , you should get catalogs from Classic Industries, Ames, NPD, Paddock etc here are also used p[arts places...
power locks appear sometimes on EBay....
on engine you can get other heads ( prob. should get some input from Q and /or Banshee on this ) , OR put a 400,428 or 455 in it ,its a direct swap pretty much , same size exterior on engine and motormounts...

you can email me direct at bsefeldt@mhinc.com and I can forward some of my "favorites' of parts places, online catalogs etc...