Cragar Center Cap

The Cragar 09090 S/S cap should fit. It's steel, and held in place with a disc that creates an interference fit on the inside of the wheel hub and is held in place with a screw.
All the pictures below are for Cragar G/T wheels. They're the painted spoke and polished rim version of the S/S, so they're very similar. They're my favorite. I had them on my Road Runner back in 1980.

My spare modern (now discontinued) 610G wheel. G is for grey, as the C is for chrome on your wheels. Your hub should measure 3" here also.
View attachment 1716347927

With vintage G/T Cap in place.
View attachment 1716347930

I.D. of vintage cap.
View attachment 1716347931

Reverse of vintage cap showing retaining plate and screw. Note the hole in the plate that lines up with the stud on the cap to keep it from turning.
View attachment 1716347932

Modern G/T caps. They should have red paint. You'll want S/S because your wheels are chrome.
View attachment 1716347934
Awesome! This is exactly the information I needed! Thanks I can now buy with some confidence it will fit. I looked at Cragars web site and Summit and there is an implication these will fit my aluminum wheels.
Thanks again for your help!