Are your rims original or aftermarket. Good hubcaps will not come off original rims. Check for damage or flattening of the bead on a hubcap that comes off.
The wheel should not need to be modified by either grinding or drilling for the hubcap to stay on
Ken
Hi Ken
All 8 rims are I assume original 4 came with the car (no spare include) -and Ipicked up another 4 to roll her around on while the good ones were cleaned up and painted. 1of the original was no good as too pitted around the Schrader valve ,being tubeless I was told it was no good.
The rims are different upon examination earlier ones are riveted later (I assume) are welded and I had fun with the brake drums and interference between the rim and drums. Again earlier drums irised off edges vs what appears to be overlapped rim edges. Yes I am confused but will persevere
Any help greatly appreciated