70 1/2 or 71 Camaro z28 manifolds ?

[BmStang]

I have a set of exhaust manifolds. I'm unclear what these manifolds would be for due to the casting dates.
70 1/2 or 71 Camaro ?
3986330 F-1-0 ...........June
3989041 G-2-0 ...........July
Thanks

[70 copo]

Late 1970 Z28. My June car already had them both and the casting dates were very close to the car's build date. These manifolds would also be acceptable for an early 1971.