Flares or tubs are the only options, keeping rear leafs or not will also influence things. I plan on a 9.5 or 10" rear on my car with a 275/18 and I will have about 1 3/8" flares with rear leafs and a Maier Panhard. I think it will end up a 9.5" with custom BS rims with a 9" in the front at about 255. You also have to plan on some level of deflection in the tire while cornering in the overall space available, I have heard 3/8 to 1/2" for deflection in a lower profile tire.
1966 GT Coupe
Not much left original
Trying to do things once
MMI CO / Panhard ~ JRI / Penske ~ Astro A5 ~ FiTech ~ MGW ~ AAW