The 68 reservior was slightly different than the 66-67. It is the bracket bolt pattern that is different. They will work though if you can bolt them up.The setup is very close on all 66-68 BB Chevelles and El Caminos with power steering. IIRC the are some small cosmetic differences in the reservior. It should work on any year Chevelle with a short water pump setup which was stock for 66-68. The reproduction kit I see for sale is usually listed as 66-68. A full kit from Gorund up used to be about $450. I haven't looked in awhile though. A similar setup was also used on BB Chevy pick ups up to 1972. Reservoir is different on it too.