i hate those weber adapters, i just found myself an offy c series manifold online. only thing is that its the older style with no EGR fitting, so i'll have to plumb my own PCV inlet.
it'll be all worth it though, a weber bolts directly on the manifold if you get a spacer(the pad is nice and wide and flat and your accelerator and choke linkage will interfere without a little riser). no leaks