In the MARC "Technically Speaking" Volume 10 pg. 18 it describes a problem caused by some reproduction lug nuts that do not have the 3/32" thread relief at the base of the lug nut as required in the original Ford specs. This was also described, I believe, on pg. 7 of the March/April 1988 issue of The Restorer magazine. The article in this link also discusses this:
http://www.fordgarage.com/pages/dangerouslugnuts.htm
In the picture below the lug nut on the left (might be an original lug nut) has the required 3/32" thread relief. The lug nut on the right is a new stainless steel reproduction lug nut purchased recently from one of the vendors. As you can see it does not have much of a thread relief at all, at most 1/32" and at one point 0.0" thread relief.
So my question is is it safe to use or could it cause problems with thread torque and possible loose wheels over time?
Thanks
Dave