If you've got the 73+ disks in the front the 17x8's with 5.48" of backspace and 245/45/17's should fit fine, that's pretty close to perfect for a set of 17x8's to be centered up front.
In the back with a 68-70 B body 8 3/4 it's probably not going to work unless you cut/trim your quarter lips back around a 1/2" or run the car at a fairly high ride height in the back.
I run 295/35/18's on 18x10's on the back of my Duster with a 1/2" spring offset and about a 1/2" trimmed off the quarter lips. I also have a 68-70 B body 8 3/4, and the backspace on my 18x10's is 7". Your 17x8" with 5.48" of backspace and 255's would only be about a 1/4" inside the outside tire wall on my set up with the 295's. Which means it would clear if you trim the quarter lips back, but probably not if you leave them stock. If you didn't want to cut or move anything, you'd want about a 6" backspace with a 17x8" and a a 68-70 B body 8 3/4.
