I've run into a subtle problem trying to install a set of cast aluminum, unilug, Center Line Auto Drag knockoffs on my '74 Challenger. The car has stock drums and wheel studs on the rear, and I started with the rear wheels. Before I ordered new lug nuts for the
wheels, I measured the thickness of the wheel mounting pad, and added
the washer thickness to that measurement, to get the proper shank length, which came out to 1 inch.

Once I got the lug nuts, I put one with a washer through the wheel to
double check that they were the proper length. The end of the lug nut
was just about flush with the backside of the wheel mounting pad, so I
thought great, no problem. I put one of the wheels on the rear, tightened the lug nuts, and to my surprise, found that they were
bottoming out on the studs just barely short of making contact with
the wheel. I checked the gap between the washer and the wheel with
a feeler gauge, and it came out to approximately .035 in.

I checked Summit's website, and sure enough, they have a lug nut with
a shank length of .946 in, which would obviously be what I need. Maybe I'm just a dummy, I don't know, but I'm usually very careful
and cautious when it comes to measuring things like this. I don't know
if anyone else has ever had the same thing happen, so I'm letting you
all know so that the same thing doesn't happen to you. I just wasted
$60 on the wrong lug nuts.

Nothing a grinder or a lathe couldn't fix.

That's not a lot of material to remove, should be able to take some off where the nut bottoms out.

thread a regular nut onto the stud, and hit it with the abrasive wheel on a grinder. the nut will ensure the threads still work, when you're done.

Really not a big problem. A grinder with do the job. It isn't a big precision cut. All you have to do is shorten the shank a bit. It don't but up to anything so it isn't a big deal to hit it with the grinding wheel.

Good thing you measured or you could open one of those "my wheel fell off, broke the studs all off" threads.

Oh I know this well, I hate unilug wheels, and I doubt I will ever
buy another set again. But these wheels were too cheap to pass up at
the time I bought them.