I say rebuild it, maybe lsx and 6sp auto nice wheels repaint, nothing over the top so if you ever HAD to sell you wouldn't be to far into it cash wise that you could get your money out. Try to think how your dad would have wanted to build if he going to do it, remember he will be there watching to make sure you build it right. But I say go for it
Another thought maybe look into how hard or if at all possible to change out the front and rear and put chrome bumpers on it??