I'm not much of expert on anything re: Vettes, but I can tell you that I've run radials on my '62 FI car since approx the first year it was born....Originally I started with Pirelli (forgot the model maybe Cintaurato) in about 1963 and have never had anything but radials since then. Can't recall the size I run but they aren't large. I've never done anything to the steering box except put some grease in it. The car now has 103,000+ miles on it. I did learn two things new from this post: 1) I now know why the hubcaps would rotate against the valve stems; and, 2) they make steel valve stems. Just imagine the time I've wasted over the past 44 years taking those !@#$%$%^& hubcaps off after almost every drive......THANKS FOR THE INFO GUYS!!! j