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.
There was a time in the mid 60s to maybe 68 in which the 442s seemed to be the dominant muscle care at least where I lived.
It had a 400 cubic inch engine. The 4-4-2 stood for four barrel carburetor. Four speed transmission and dual exhaust.
Those 442s were beating the SS-396s, and GTOs too.