Tire Size for 5.5 small bolt rally wheels on 64 Valiant 200

i've never had the two side by side, although having worked under both, i think the valiant is a a little more narrow toward the top. but i don't see a 245 being a problem to fit if you're not super low and it's got something close to factory rear end width (you're fitting a 9" down the line, no?)
I am, yes. It's about 1" narrower than stock. I'm overdue to get the Percy's tool on it anyway, so I need to do that.