The DC and YS wheels are full size chevy, 68 to 70. 15 X 6
The FW is the most common ralley wheel, used on Chevelles, and MC early 70's to late 70's. 15 X 7 with the same back spacing as the Z/28 YH wheel from 69, but some subtle diffences in hole size.
http://www.camaros.org/forum/index.php?topic=660.0
http://www.chevytalk.org/fusionbb/sh...post/last/m/1/