Another option I've played with is using the Rochester 2G 2bbl carb instead. I'm not sure how tall it is, but my memory of the one on my '76 305 Camaro is that it was pretty short. But it was also used on the 229cid 90 degree V6 that replaced the 250 L6 in the passenger cars. The air cleaner for that used a 2.8" x 9.6" air cleaner. I'm not sure if it had a dropped base like the V8 2.5" x 12" 2bbl air cleaner, but the extra air filter may help overcome restrictions of the closed snorkel air cleaner. And it probably wouldn't need a spacer for linkage.
