Screw in studs - Replace with bolts?

I have some Moser axles with screw in 3" studs. The way it sits now, I can't mount my rims to the rear because I have closed ended lug nuts, which I have open ended nuts on order, but it will take them a week or two to get here.

Would it be safe for a 4cyl seeing no track time to just use shorter grade 8 bolts untill I can get the proper lugnuts?
 
are you talking about replacing the studs with bolts? or replacing the lugnuts with grade 8 nuts?

if it's the nuts, then no. the lugnuts are usually acorned. i, myself, wouldn't feel comfortable with driving around on hardware bolts, either.