Here is a link to Kinsler FI systems, and some pictures of some intakes.
http://www.kinsler.com/i_manifolds.htm
You'll notice that the upright BBC have the staggard bells, but the cross ram doesn't. The upright BBF, with symmetrical port heads, also has the staggard bells, though not as drastic differences as the chevy. The upright BBC with symmetrical port heads have the same height.
I don't relly know for sure, but if you were to call them, I'm sure they know why.
Also, if you find an old FI intake, they will completely refurbish it for you, or do an EFI conversion to it.