I like the idea of swapping carbs around too - clever. While you've got both carbs off, take a look down the manifold and a cautious feel with some coathanger wire to see if there are any bloackages (unlikely though). When people can't get manifold gaskets, it's not unusual for them to buy sheet gasket aqnd cut their own. Not a bad thing, but if they don't cut the "centre hole" out enough, it can be a big restriction (working in the rain at 2am after several beers doesn't help concentration at gasket cutting time either
).I hear ya Squirralien about cost (and if she runs on the front carb, they can't be too bad despite the years of crud on them). If you can change carbs around, you can give a stromberg an overhaul without experts. Kits are around $45 each, and unless the throttle shafts need bushing will solve most dramas.