I don’t think wheel spacers are legal, ima read my 2008 nhra / ihra rule book right now. ill come edit this with what i find.
edit.
permitted, must be hub-centric or lug-centric and must fit with minimal clearence to retain concentricity.
wheel spacer must not reduce the minimum permitted thread engagement below the limits established by fastener diagram. No stacking of wheel spacers allowed.
basically means, a 7/16th-inch stud must be thoroughly engaged through the threads in the hex portion of the lug a minimum of 7/16th-inch.
I dunno if it was all posi locked or spooled cars, or just cars with slicks.
But I remember on the RWD cars last year, they said No closed end lugs go thru tech.