Thread size of the lug nuts is 1/2"x20tpi. Most any speed shop will have chrome lug nuts. I'm not sure about stainless though.
Old trucks and old trailers . . . a comfortable combination!
A-6E All Weather Attack Driver, BUFF
USN Aircraft Maintenance Officer, Ret.
'91 Suburban R-2500 w/BBC
'78 Honda GL-1000
'72 Triumph T-100R Daytona