2004 Alloy wheels on 1978 K20 HELP!!

[78K20]

Can someone please advise me where to get the parts I need to put these wheels on my truck?

I've got a 1978 chevy K20 ( 8 lug set-up ). Been running the stock steel wheels.

I just bought a set of 2004 aluminum alloy 8 lug wheels to put on. I want to hide the hubs under a bowtie center cap. My truck is full time 4X4, so I have the large front hubs.

My truck has the old style studs, American thread, I think 9/16"? Whatever came with the truck in 78. I need a lug nut with the external thread for the center caps to attach to. I also don't know what GM Bowtie center caps to look for. I saw a late 70's K20 truck a couple years ago, with the exact same wheels & bowtie center caps. So I know it can be done, but I don't know what caps to get.

Below is the exact same wheels I have, and the center caps I would LIKE to have. Just don't know if they make a center deep enough to clear my hubs.

Anyone have any experience with this, and care to share? Thank you.