My memory may be going but when I was growing up in the 60s Buick had a 455. I think Olds did too and they were totally different engines.
Also totally different from the Chevy 454.
I just know about the Olds 442, didnt know about a 455. I only heard of the 442 and the 454. I had family that had cars with both of these two. The 455, if it was an earlier engine, was before my time.