Did COPO,s come with 14 or 15 inch wheels when they had the dog dish caps?
That would be the standard 14 x 7 [XT code] wheel.
From the ASK CRG! - ARCHIVES (http://www.camaros.org/askcrg-archives.shtml) (question #86):
"COPO (Central Office Production Order) 427-engined cars, unless ordered with the ZJ7 rally wheel option or the COPO 9737 sport car option, came with the same wheels used on other non-rally 1969 SS cars, the 14x7 XT steel wheel. This same wheel was also used on Chevy II SS in 1969. We haven't looked beyond 1969 to determine later use."
Ed
When I first joined CRG I spent hours reading in the ARCHIVES. I suggest all members spend some time in them.