NEW GUY {kinda}
I don't think you have enough rear tire! LOL.
Reminds me of my ol' '69 Dart racecar. I had 14x32 slicks stuffed under the rear with stock-height (but lengthened) wheel openings. The car sat much lower than yours and I had to jack the tail waaaay high in the air and disconnect the back of the rear leaf springs in order to pull a rear slick. I don't remember the rearend width but it was short.
Your '67 is looking really sharp!