NHRA regulations

battery hold downs are suppose to be 3/8 inch diameter...

wheel studs are follows...

The thread
engagement on all wheel studs to the lug nut, or lug bolt to wheel
hubs, must be equivalent to or greater than the diameter of the
stud. Length of the stud/bolt does not determine permissibility;
length of the engagement between the stud and lug determines
permissibility.

that mean if you 1/2 studs...the threads must be 1/2 inch into the lug nut...