Ford 9" Rear Axle Vent

[Old Style]

Not sure if this confilcts with your post, but Art Morrision makes a puke can that mounts on the floor or trunk pan above the pumpkin. I've never seen anyone use this and I'll look for the link, but I am considering this as an option.

Edit -- Here's the link, middle of the page:
http://www.artmorrison.com/2006cat/48.pdf

This is what I have been using for the infamous spitting, it took several failed concepts before I went to the trunk. In a previous comment, he is correct, if you are lower than stock there is no room underneath, at least on an A-body. For reference I am running a 9" with Tru-Trac.