Just for the sake record keeping, finished up the carb install tonight without a hitch. Maybe I'm the last guy to figure this out, but there are actually two different clamps that came from the factory, as I presume this set is original. The rear band clamps, the ones that clamp carb to air plenum boots are different from the band clamps that connect the boots between carb and engine. The rear plenum clamps have a longer "tang" that slips under the nut side of the clamp. I just didn't notice this on my first attempt. Tonight, with the right clamps in the right place, no problem at all. And I don't find these "old hose clamps" a problem at all once I put the right ones in the right places. Again, this is for a '75 550K, may be different for other models.