18" dodge high clearance wheel

I have a set of the dodge 18" x 3.75" high clearance wheels. Does anyone know what caps will fit. I measure 7" for the clips
Im also interested in trying to put a wider rim for the rear. My tire options are very limited for the rear since its not even 4" wide. Id like to go 6". I measure the inside of the rim right at 16"

 

Weld 2 together for the back , back in the 60 it was done occasionally. Get caps at a motorhome/RV store.

 

Send them to wheelkid and have them widened. I believe you will need to run the smaller dog dish Dodge caps on those wheels. (take a look at early Dodge trucks_