The Stovebolt Site Forums The Parking Lot Big Bolts 1958 GMC 370

I have 1958 GMC 370. Last time it was on the road was 1981. The Driver front brake was stuck. The tire was removed and lug nuts put part was on, and left on the ground. I Replaced the wheel. Now the lug nuts only screw part way on. I put a wire wheel on a drill but not much help. So my next thought was to get a 3/4 tap and die to clean up the threads on the studs and lug nuts. So my question is. I know it left hand threads and I think it 3/4... but what is the thread count? I went to a local auto parts store and the guy said it was 14. I'm pretty sure thats wrong. Since I have to order it online. I want to make sure I order the right one. Any Help Please