Skipmurf--
If you had XAS's on your Healey in 1972 that would have made you somewhat of a pioneer. Back then the Michelin X was a popular tire for British and other sports cars and though they were good in the rain my recollection is that they had a relatively flexible side wall and did not have the best directional stability. The XAS tires--brought out in about 1965-- were originally intended for the larger, faster European sedans such as Citroen DS19's (I believe they owned Michelin at that time), BMW 2500-2800's, etc.
I put a set of 180 XAS's on my 100 a few years back when the XZX was discontinued in the 175 size and I think they are wonderful. They give great tracking at highway speeds and feel very grippy in wet or dry. They fill the wheel openings very nicely and provide a little extra ground clearance--always a good thing on a Healey. I use tubes with my wire wheels.
I believe they are now made some place in eastern Europe and I have not had or heard of any quality problems.