it's your car do what makes you happy. with that being said......do keep all the original stuff so you could change it back if you were so moved.
zbo2 has a point: It is your car... Now, if you had posted under Originality, I'd be saying, "No... No... NO". But you asked this question in General Discussion. So what will make you happy for your car --long term?!? Why did you buy it? For what purpose will you restore it? Will it be a trailered show car? (Which in your case, with those changes it will always be a clone...) A drag strip champion? (Certainly not, without modification) Or a cruiser? (For which a 327 with PG with a little paint and chrome was made for.)
A few years ago, I bought a Camaro similar to what you have. A previous owner had started the cloning process. It has actually cost quite a bit of money to restore it back to original. And I'm still working on it. The truly sad part is, he scrapped the original motor. In that sense --even though his intentions were good and he passed it along at a fair price-- something irreplaceable was lost to the hobby. I've got a restoration buddy who says, "It's like trying to replace a unicorn. There aren't many left around!"
Also, if you make changes to the car and some day decide to sell it, document what you change as you go and sell it for what it really is. We all owe that to the hobby!
Let us know what you decide and post pictures along the way.