need help with my new center caps

I went to a car show recently in Carlisle, PA and bought some cheap (but decent) trim rings and center caps. If anyone knows how these center caps work, they use special lug nuts with threads on the outside where you screw plastic caps on top to hold on the center cap itself. Well, the guy thought since my caprice is such a big car that it would use the half inch size heavy duty lug nuts, and me not knowing what size the bolts were took his word for it. Well after getting home from the 10 hour drive i found out they're too big!!! So the trim rings are on but as you can see in my signature below i just taped on the center caps to get an idea how they'd look. I think the real size i need is 7/16, but im not sure. Does anybody know where i could get these special lug nuts?

Yes, standard size is 7/16" on 5-on-4.75" bolt pattern rims. 1/2" are for the 5-on-5 size. Some of the later 5-on-5 use metric 12 size lug nuts.

I like the new look for the wheels by the way, reminds me of a 9C1

hey what did u do with the old center cabs the originally ones? you want to get rid of them?

hey what did u do with the old center cabs the originally ones? you want to get rid of them?

Sorry, i'm planning on keeping those just so i can have the original parts to this car.

Nevermind, i found the right lug nuts online somewhere. (Although i had to pay double the price as the first ones!)

The lug nuts you got online, do they have thread on the outside of the lug nut? Those caps you got look like the ones on my 1994 C1500 pickup. They are held on by plastic caps that screw onto the metal lug nuts. The lug nuts have thread on the outside of them to accept the plastic cover caps that hold the center cap in place. I would think the Chevy dealer would still carry these in stock and I remember getting replacement lug nuts at Autozone.