I would go 235 on the front and 255 on rear. This will give you the look your after and still work on the 7" rims without excessive tire bulge. Just my opinion though. Do you have the engine back together and the car running and driving yet?
Just have to put the valve cover and carb on. Everything else is done. Hope to have it running by the weekend. I am leaning towards the 235/255 combo. I think the 275's will be too much for the 7" rims. Since I'm ordering the tires off of ebay I don't want to get stuck with something that doesn't fit, look right and\or dangerous.