I'm getting ready to do this swap to the Weber. Reading the instruction it seemed simple. Reading this thread, it seems as confusing as it can be; thought when done we are supposed to end up with 1 gas line going to it, one vacuum line for the distributor, and one for the crankcase breather, blocking off everything else from the stock setup!
This thread seems to be detailing there is a heck of a lot more "mods" and "work-arounds" than a clean straight install! Now considering just getting a new Summit rebuilt stock carb and slapping it on.