I gave a backdate some serious consideration for my 77 Targa after purchasing her last year. She came with a Euro 3.0 and I decided to install some sport seats and a sport shifter along with a suspension refresh. The result is a light, fast well sorted car that is loads of fun
She is currently in for a corner balance, alignment and ride height adjustment.
Here is a little inspiration for you
My vote is keep it stock and spend a few $$$ on a light restoration.