That's a tough call. You may have to measure what you have carefully and compare. The 15x7"s with 4.25 backspace barely fit on my 70 Swinger. I can't slide my fingers between the sidewall and the quarter lip. Things are tight. The inside clearance (backspace) is usually not an issue with these cars.
My inner quarter lip is shaved off for fitment. That's how I fit the 8 inch. If I'm thinking correctly , the 1 inch less backspace should wash with the 1 inch less width. I'm thinking it should fit the same on the outer and more room inner.