Thanks guys, that helps. There is a hose that comes off the distributor, goes into a "T" fitting, and one branch goes to the tri-plug that goes into the carb base, and the other branch goes to the other side of the carb and connects to something. Guess it doesn't matter which hose I use to connect to the Weber, as long as I cap the other one. There was a long section of thin hose that came with the kit, and my guess is this is the vacuum hose that goes from the carb to the distributor. There's also a section of hose that looks to be fuel line, so I'll have some extra in case the stock fuel hose will be too short, which I think it will be, since the fuel inlet on the Weber is in a different location.

I'm tempted to just disconnect all those hoses on the stock Mikuni and leave them there, and put bolts/clamps in the ends of the water hose and fuel return hose. That way, the "original" hoses will still be there, more or less in their original location. But I'm also thinking that can't be a good thing, to leave all those hose ends open like that? When I noticed the Weber only had one vacuum hose fitting, it's no wonder it's not street legal in CA. There's probably no way it'd pass smog.

But I'm really liking those Weber mechanical secondaries! Looks like I'll tackle the install either Fri or Sat, so wish me luck!