Odd-ball '75 Parisienne

Howdy, I'm the new owner of a super clean '75 Parisienne Brougham with 21k miles on it. Purchased it from a family friend who's father had passed away and was taking up valuable garage space. According to the internet, this car came standard with a 400cu.in engine and had an optional 455. Odd thing is, mine has a 350. Doesn't look like a swap either, as it has a factory sticker above the sealed beams that confirms it.

The car had been sitting untouched for 8 years before I had it towed to my garage and tinkered with. Installed a fresh battery, sprayed a little carb cleaner into the 2bbl and with some motivation, it started right up. Drives fine too despite flat spots in the tires. I guess I was lucky, hadn't expected it to catch at all.

I came here to get as much informed as possible on this car and what I can do to make it run at its best. Already have some big plans but for now, I just want to clean it up a bit. Thinking new plugs & fluids at least. Any advice or recommendations would be most welcome. Thank you