A little story about the portawalls, in 1956 we had a friend that had a 46 Chevy with portawalls, he wore thick glasses and we nicked named him "Portawall Peepers". Another thing about the portawalls, when you were going 60 or over they would flare out from the tire. Even back then, portawalls weren't the thing!
Why not just get whitewalls?
