Since the weather has warmed up, I'm able to sneak out into the shop and work for a couple hours at a time and get some things done without freezin' my ass or waiting for the shop to warm up just to turn around and go back in about the time it gets comfortable enough to work.
I dug through my box of parts I made when I had access to the CNC about 20 years ago and came up with a velocity stack that fits the Amal on the BSA. Took the K&N off the Ducati and put the two pieces on the bike to see what it looked like. The air filter has an angle on the inlet. It just clears the cardboard template for the sidecover but in use it would probably rub the paint off. If I put an air filter directly on the carb, no clearance issue at all. I need to have Surly weigh in on what I've got and then get to gettin'. Haven't done dooky on the bikes all winter long. Again.
I've only got one complete velocity stack but I do have another base already machined up. Making the actual stack part isn't all that tough. The Prez might have a pen and phone but I've got aluminum and a lathe. I like the look of the stack with the filter and everything clears the fuel taps. I think I might be on to something here.