Well, the 68 I bought has those funny little drag wheels on the front and since they are pretty squirrely in the streets I thought to change mine out too. I found a site on the internet (unfortunately I didn't bookmark it and have forgotten what it was, but it involved Car Craft Magazine, I think) and they listed a bunch of car/wheel sizes from Weld Racing. Weld gives the fgf either a 14x8 or 15x8 as the correct wheel size with the 4.5 in b.s. for both front and back.
I'm sure others will give you more information that I as I have only been involved with this for a short time.
