You wanted the 2902 for rectangle port heads, the 2904 is for oval port heads. Maybe not. Hmm.
I have a 454 gen IV block with the 2902.
Interesting problem now that I've looked at the 2161, this is for the oval port heads and the pic does look like oval port.
The head part number tells me 396, mine end in 990 which are the square port.
Someone with more knowledge will tell us both what's going on here.