235 70 15 rear early abody

Someone tell me what max tire is in a 65 Barracuda with a stock A 8 3/4 rear. 205/70R14's currently on rallies. Want to go 15's as i have 15x7 SBP reverse Centerlines from a Chevy 2 so they are more back spaces than front. Maybe 5 back and 3 front. Redrilled.