what might they come off of?

[alsdemon]

hope to use on a 360 non smog motor.

 

[C130 Chief]

Look like 74 A-body manifolds. They have the "tabs" for the later heads, but are not drilled for air injection. Should work fine on the street up to about 300 HP. Beyond that headers.

 

[crackedback]

Drivers side is a 1975 model year manifold

Pass side is a good piece. The casting date is just starting to be visible in lower rt hand corner of the pic