I run P205X70R15's on the front of my '32. It depends on how low you want the front end to be. I would suggest cutting a couple of 3/4 inch plywood discs in the diameter of the front and rear tires you are considering, bolt them to your hubs, and see if it sits the way you want. You can block up the other side to hold it steady or cut two additional discs if you are ambitious and have the wood. Cut the front disc down to the next smallest tire's diameter if you think it is sitting to high and repeat if necessary.