Here is the list I got from one of White Trash's posts:
Seville:1976-79
Appollo:1973-75
Camaro:1967-81
Firebird:1967-81
Nova:1968-79
Omega:1973-79
Phoenix:1977-79
Skylark:1975-79
Ventura II:1971-77
I got mine off of a '79 Seville. I'm putting mine in a full-bodied 4Runner and am gonna experiment with add-a-leafs and toyota leafs. I'm hoping the spring hangers are gonna be welded on tomorrow for it. I'm gonna cut the bushings, sleeve and eye sleeve to fit in 2-1/2" CJ spring hangers that I have. From bushing end to bushing end they are like 3-3/8" wide, so unless you use the stock Caddie spring hangers or make your own you kind of have to do some adapting. But, it seems like these things will be really flexy.