They were neutral. That is the wheel hub sat in the middle of the wheel which was narrow by today's standards. Those tires were 6.10 inch wide in the middle of the balloon sidewalls with only a four inch wide tread. They also had a bias ply construction, so they would roll under like a motorcycle tire, peeling the tread up off the pavement.
Original equipment for your car (brakes, wheels, tires) were designed for no more than 45 mph because that was as fast as you could find a speed limit back then.
Unless you plan on having your period piece towed to car shows on the back of a trailer I would be looking at bigger brakes, wider wheels and radial tires which don't look stock but can drive at modern interstate speeds without killing you or someone else.
Kelsey-Hayes still makes your original 14 inch steel wheel in it's original 5.5 inch width for sale to the reproduction market: but I would buy a Corvette wheel (doesn't have to be a Rally, plain steel works) in a 15 inch size and wider width. The Corvette still used the same front steering parts as the Impala did in 1964 (they were used up through 1982) and are also reproduced. They were rated at a higher speed than the passenger cars where.
Last edited by Big Dave; 06-30-2019 at 06:19 PM.