The 502's and 454 Magnums were not sold by Merc with a Y pipe as standard. That's why it's not shown. Take a look at a 7.4 from that year

[http://www.mercruiserparts.com/Show_...%2E4L+BRAVO%29
Fountain has it -
Sounds like you have the old style (#11) if you click on the part number you can see a photo of the current replacement.

yup, that's what i have. I just ordered the older p/n from a local shop. I see the new part is probably the way to go though. I already have the 807166a-1 flaps, and they are huge. Not sure how they are supposed to seal, they are bigger than my pipe is. Only thing i can see is they seal against the plastic frame pieces.

Ok, i get it now, i'll get those. Thanks for the help guys.