I would make under the hood very stock looking. I.e. use a b-block, like a 383 or 400.
Stroke it, put in some 440source heads, MP dual-plane intake (looks like a stock iron one), and roller-cam it.
What's the original color again? I would paint it the original color, but add things like billboards and a wing.
Wheels are easy to change, so whatever you want to go with there. Keep interior stock looking (I'd add a Rallye dash myself if it didn't already have one).
Good luck!