Don't they require a special offset dizzy, while the Offy 5698 and 5615 do not?
I have one of those, which is going on my 360 build. I'll verify which one it is when I get home. The one I have required a little work with a dremel and I got some spherical washers for a solid fit since it's made for the older 273 with the intake manifold bolt angle.
There is also a taller one, I don't know the part number. I can try to find it when I get home.