Grandville modification

I've always been a car guy and always admired  GTO's...only problem was they were expensive!  So I gave up on that idea. I later discovered that was probably the best thing that could happen for me because I didn't realize  that they could be very fast as they are and I probably would have eventually wrapped myself around something immovable... I  always liked convertibles so about 25 years ago Grandville on a car lot caught my eye. I passed by several times a day while at work and admired it from afar. I realized much later that  it has the same Coke bottle shaped quarters (although larger) as the GTO! (So that's what I like about that car). I bought that car and changed the colors inside and out, drove it a long time then the 455 went out. Now that I'm older and wiser I asked a friend to find me an LS2 and a newer transmission with overdrive to put in it. I will save the 455 and original transmission in my garage. I want to be able to reinstall my AC system if I can and would appreciate any helpful  suggestions for suspension ect. Thanks.