Pretty sure I know the owner and I'm quite sure he is/was after the correct tire tread "look". Unfortunately, Avon do not make 60 series tires until they get very wide.
The options are limited in "15 tires. Tire Rack lists one that looks good on paper but won't be to everyone's liking. It's the Yokohama Ascend GT. Dry traction is the only parameter I care about but it also ranked high in "comfort" for what that's worth in a 55 year old noisy car. :rolleyes: