I responded on your other thread....
http://www.ultimatesubaru.org/forum/showthread.php?t=69300&highlight=holley
I used the weber adapter, then 2 weber spacers (.5" each), then a standard 2 bbl -> 4 bbl adapter. I had to widen out the holes on the 2 bbl side of the adapter to fit the weber pattern.
It ran great at WCSS7, but for daily town driving, or just slow trail riding, it was a pain because I had to keep it revved to be happy.
I have put my weber back on, and it's much happier, though since I still have the 2->4 adapter, I may someday try one of the 390 cfm's just for kicks....