[ QUOTE ]
FYI, The above 5/8" x 1" oblong hole wheels were only made/used on Jan-early June 70 Z-28's, before changing to 13/16" x 1" holes on late June/July Z's, which stayed through the 1974 Model Year.
It wasnt until the reintroduction of Z-28 in 77' when the ROUND hole wheels came out.
[/ QUOTE ]
Here's a link supporting Chuck's comment, to some research I did on the wheel hole size vs date "timeline" if anyone is interested.
http://www.nastyz28.com/forum/showth...ght=valve+hole