Oil pump housing question

[gteatr6]

I have a brand new pump housing but the number comes back for a Cadillac. Looks exactly the same except for the small (pressure relief?) is pressed in farther on the cadi one. First 2 pics are the new one, second two are off a buick. Can I use the new one and be ok? I'd probably use a known buick spring in it though.

 

[Nick Micale]

That is a filter housing from a Buick engine.

In 1981-83 Cadillac, and other makes as well, used a 4.1 Buick engine in some of their lines of cars.

 

[gteatr6]

Thanks